Prepare your ingredients: Ensure the sushi rice is cooked and cooled to room temperature.

In a large bowl, combine sushi rice, tuna, mashed avocado, green onions, and beaten egg. Mix gently until combined but still chunky.

Form the mixture into patties approximately 1 inch thick using wet hands to prevent sticking.

Heat olive oil in a non-stick skillet over medium heat. Cook patties for about 3-4 minutes on each side until golden brown.

For the sauce, mix mayonnaise and sriracha in a small bowl until smooth; adjust spice level as desired.

Assemble the burgers: Place patties on toasted buns or lettuce wraps, top with sauce and additional avocado if desired.