- Share + savor
I have a cookbook! - Buy Now
Tuna Tostadas with Scallion Sauce
These tuna tostadas are made with with soy marinated fish over mashed avocado combined with lime juice and fried scallion sauce.
jump toRECIPE
This post may contain affiliate links, which means that I make a small commission off items you purchase at no additional cost to you. Please read my policy page.
These fresh and flavorful tuna tostadas are layered with creamy avocado mash, soy-marinated ahi tuna, and a fragrant fried scallion sauce for the perfect mix of crunch, heat, and umami. Inspired by both Mexican and Asian flavors, this easy 30-minute recipe is perfect for warm-weather dinners or casual entertaining. If you love bright, citrusy seafood dishes, try my baja fish ceviche tostadas or this seared ahi tuna salad next.
Why You’ll Love This Recipe
- It’s quick and easy – Ready in under 30 minutes with minimal cooking, making it perfect for busy weeknights or warm summer evenings.
- Flavor-forward – Creamy avocado, soy-marinated tuna, and crispy tostadas create a restaurant-worthy balance of creamy, salty, and spicy.
- Make-ahead friendly – The scallion sauce can be prepped days in advance so assembling dinner is fast and effortless.
Key Ingredients in This Recipe
- Corn tortillas – Corn tortillas are fried until crispy and golden brown for tostada shells. They act as the base for the marinated tuna mixture.
- Tuna – “Sushi grade” is the term given to a fish that can be eaten raw. It is bled and gutted quickly after it’s killed, then flash frozen at an appropriate temperature to kill any potential parasites. Look for tuna with a bright red color and a shiny look. I’ve shared tips below for purchasing sushi-grade fish. Use a sharp knife to thinly cut the tuna. I find the thin slices are much easier to eat than cubed ones.
- Soy sauce – Briefly marinating the raw tuna in soy sauce adds to and complements the flavor of the fish.
- Green onion – Thinly sliced green onions are simmered in hot oil to create a fragrant and flavorful sauce used for topping the tuna tostadas. Green onion is the same thing as scallions, it just depends on what the area you live in calls it.
- Garlic – Chopped garlic rounds out the flavor of the scallion sauce.
- Avocado – Ripe avocados are mashed with a little salt and lime juice until smooth. The mixture is spread over the tostada as a base for the thin pieces of tuna.
- Lime juice – Acidic lime juice helps to add flavor to the creamy avocado purée.
- Serrano – Thin slices of serrano pepper add just a bit of fresh heat to the tostadas. Serrano peppers are long and bright green, similar in flavor to jalapeños, but pack about five times the punch. If you can’t find serranos, jalapeños will do.
A full ingredient list with exact amounts can be found in the recipe card below.
Pro Tip
Chill the tuna in the fridge before slicing — slightly firmer fish is easier to cut thinly and cleanly. Always use a very sharp knife to slice against the grain for the best texture.
Where to Buy Sushi Grade Fish
- At your local fish market – Many fish markets offer selections of fresh fish like tuna or salmon that you can use for raw recipes like this. Then, ask your fishmonger for more advice! They are a great resource.
- At a Japanese market – Many markets sell pre-packaged cuts of sushi-grade tuna in the refrigerated section. This keeps it easy for use in this recipe!
- Buy online – So, if you don’t have a place to buy fresh high-quality fish locally, I recommend ordering online. There are plenty of places where you can get fish shipped quickly though it will be more expensive since it is being shipped!
Tips for Cutting Tuna
- Use a sharp knife! A sharp knife will help you thinly slice the tuna.
- Chilled tuna is more firm and will be easier to cut.
- Cut the tuna 90º against the way the sinew runs.
Swaps and Substitutions
- Swap the tuna for thinly sliced salmon or yellowtail for a different flavor profile.
- Substitute the scallion sauce with chili crisp, salsa macha, or your favorite hot sauce.
- Store-bought tostadas work fine if you don’t want to fry your own.
How to Make Tuna Tostadas (Step-by-Step)
Add the oil to a small saucepan and heat over high heat until the oil sizzles when a piece of scallion is added. Add the green onion, garlic and sesame seeds to a small bowl.
Carefully pour the hot oil over the green onion so it sizzles and is fragrant, stirring to combine. Let cool and season with salt. You can make the scallion topping up to a week in advance and stored, refrigerated, in an airtight container until ready to use.
Fill a large cast iron pan or sauté pan with enough vegetable oil to reach ½-inch (1.3cm) up the pan and heat through. Test a corner of one of the corn tortillas, it should bubble when added to the hot oil. Working one at a time, add the tortilla to the hot oil and fry until crispy on both sides, about 1 minute per side. Remove to a paper towel-lined plate and repeat with the remaining tortillas.
Arrange the thin slices of tuna on a plate. Drizzle with the soy sauce and turn to coat. Set aside.
In a medium mixing bowl add the avocado and lime juice. Mash with a fork until smooth. Season to taste with salt.
Evenly spread the avocado purée over the tostada shells. Top with slices of the marinated tuna, and then with a spoonful of the scallion sauce, serrano slices and cilantro. Serve immediately.
How to Serve Tuna Tostadas
- Serve immediately after assembling to keep the tostadas crispy.
- Top with thin slices of serrano or jalapeño for extra heat.
- Garnish with microgreens or chopped cilantro for a fresh finish.
- Pair with a cold beer, margarita, or sparkling water with lime.
How to Store Tuna Tostadas
- Store components separately: keep marinated tuna, avocado mash, and scallion sauce in airtight containers.
- Refrigerate for up to 1 day for best freshness.
- Reheat tostada shells in a 350°F oven for 5–7 minutes to restore crispness.
- Assemble just before serving to prevent sogginess.
FAQ – Frequently Asked Questions
Can I use canned tuna instead of sushi-grade tuna?
For best flavor and texture, use raw sushi-grade tuna — canned tuna will change the dish completely. If you must substitute, use it in a cooked or chilled variation instead.
Where can I buy sushi-grade tuna?
Check your local fish market or Japanese grocery store — they often label it as “sashimi-grade.” You can also order from trusted online sources like Honolulu Fish Co. or Catalina Offshore Products.
What’s the best oil for frying tostadas?
Use a neutral, high-heat oil like vegetable, canola, or avocado oil for even crisping without burning.
Can I make the scallion sauce in advance?
Yes! You can prep the scallion sauce up to a week ahead. Store it in an airtight container in the fridge until ready to serve.
Other Recipes to Try
If you enjoy this tuna tostada recipe, give these a try:
- Sesame Crusted Seared Ahi Tuna Salad
- Baja Fish Ceviche Tostada
- Yellowtail Sashimi with Serranos
- Coconut Shrimp Ceviche Tostadas
Thanks for cooking with me! If you made this recipe, leave a 🌟 rating and share your thoughts or tips below. I’d love to hear from you!
Tuna Tostada with Scallion Sauce
Rate this Recipe
Ingredients:
For the fried scallion sauce:
- ½ cup vegetable oil
- 4 green onions, thinly sliced
- 3 cloves garlic, chopped
- 1 tablespoon white sesame seeds
- Kosher salt, as needed
For assembly and serving:
- 6 (6-inch) corn tortillas
- Vegetable oil, as needed, for frying
- ½ pound sushi grade ahi tuna, thinly sliced
- 3 tablespoons soy sauce
- 1 large ripe Hass avocado
- 1 tablespoon freshly squeezed lime juice
- Kosher salt, as needed
- 1 medium serrano, thinly sliced, for serving
- Chopped cilantro, or micro-cilantro, for serving
Instructions:
For the fried scallion sauce:
- Add the oil to a small saucepan and heat over high heat until the oil sizzles when a piece of scallion is added. Add the green onion, garlic and sesame seeds to a small bowl.
- Carefully pour the hot oil over the green onion so it sizzles and is fragrant, stirring to combine. Let cool and season with salt.
- The scallion topping can be made up to a week in advance and stored, refrigerated, in an airtight container until ready to use.
For assembly and serving:
- Fill a large cast iron pan or sauté pan with enough vegetable oil to reach ½-inch (1.3cm) up the pan and heat through. Test a corner of one of the corn tortillas, it should bubble when added to the hot oil. Working one at a time, add the tortilla to the hot oil and fry until crispy on both sides, about 1 minute per side. Remove to a paper towel-lined plate and repeat with the remaining tortillas.
- Arrange the thin slices of tuna on a plate. Drizzle with the soy sauce and turn to coat. Set aside.
- In a medium mixing bowl add the avocado and lime juice. Mash with a fork until smooth. Season to taste with salt.
- Evenly spread the avocado purée over the tostada shells. Top with slices of the marinated tuna, and then with a spoonful of the scallion sauce, serrano slices and cilantro. Serve immediately.
Notes:
Chill the tuna in the fridge before slicing — slightly firmer fish is easier to cut thinly and cleanly. Always use a very sharp knife to slice against the grain for the best texture.
Nutrition:
Calories: 434kcal | Carbohydrates: 8g | Protein: 16g | Fat: 39g | Saturated Fat: 6g | Polyunsaturated Fat: 18g | Monounsaturated Fat: 12g | Trans Fat: 0.2g | Cholesterol: 22mg | Sodium: 783mg | Potassium: 478mg | Fiber: 4g | Sugar: 1g | Vitamin A: 1447IU | Vitamin C: 10mg | Calcium: 47mg | Iron: 2mg
DID YOU MAKE THIS?
TAG ME ON INSTAGRAM TO BE FEATURED ON MY STORIES! @cookingwithcocktailrings
)
)
)
Amazing!
Thank you so much!! One of my favorites!!