A mayo base holds everything together with a touch of sriracha heat, soy sauce depth, green onion freshness, and a squeeze of lemon, letting the delicate lobster shine in this crispy rice topping.
Rinse the sushi rice in a fine mesh strainer until the water runs clear. Cook with 2¼ cups (532g) water and bring to a boil, cover, then reduce to low, and cook for 20 minutes until tender and the water is fully absorbed. (I also like to do this in a rice cooker)
Whisk together rice vinegar, sugar, and salt. While the rice is still warm, sprinkle the seasoning mixture over it and fluff gently with a fork. Let cool.
Line a quarter sheet pan with plastic wrap. Spread the rice into an even ½-inch layer and press firmly so there are no loose grains. Cover and refrigerate for at least 1 hour, or overnight for best results.
Lift the rice block out using the plastic wrap overhang. Using a wet knife blade, cut into 12 even squares or 24 rectangles (if you prefer no cut side).
Add the chopped lobster, the whites of the green onion, mayonnaise, sriracha, lemon juice and soy sauce to a food processor fitted with the blade attachment.
Pulse to combine until finely shredded but not puréed. Season to taste with salt and chill until ready to assemble the crispy rice.
Heat vegetable oil in a skillet to 375°F (190ºC). Fry in small batches undisturbed until deeply golden on the bottom, about 2 minutes. Flip and fry for an additional 2 to 3 minutes until crispy all over. Drain on a wire rack.
Top with a dollop of sriracha and the remaining green onions. Serve immediately.