Drain the oil from the canned tuna using a strainer.
Mix tuna with sriracha, mayonnaise, soy sauce, and lemon juice until well combined.
Put the rice in a bowl and let it cool.
Add lettuce, cucumber, and avocado on top of the rice.
Spoon the spicy tuna mayo mixture over the vegetables.
Garnish with seaweed flakes, sesame seeds, green onions, or other preferred toppings.