This dish is inspired by the popular pairing of limes and peanuts in Thai cuisine, though this dish is not traditional. The sharp and acidic lime balances out the creamy nutty peanut butter and cuts through the fat for a tangy noodle dish.
Heat a large saucepan over medium heat, add the vegetable oil and heat through. Add garlic, stirring constantly until fragrant, about 30 seconds.
Add the coriander and cumin and cook for just a few seconds before adding the orange juice, lime zest, peanut butter, tomato and soy sauce, stirring until combined.
Add the lemongrass then bring to a simmer, cooking until slightly thickened, about 10 minutes.
Remove from heat and let cool slightly then blend until completely smooth. Return the sauce to the pot and set aside.
For the noodles and assembly:
Place the rice noodles in a large bowl filled with hot water and let soak until tender but not mushy, about 5 to 10 minutes. Drain and set aside.
Cut the limes in half. Heat a grill pan over medium-high heat, add the limes cut side down, cooking until slightly charred, about 3 minutes. Remove and set aside.
Add the noodles to the sauce, tossing to combine. Serve the noodles topped with the peanuts, chili onion crisp oil and cilantro leaves and with the charred limes.