Cook quinoa according to package directions. Spread on a pan to cool.
In a small bowl, combine mayonnaise and sriracha sauce.
Using a 1 cup dry measuring cup, layer ¼ cup cucumber, then 2 tablespoons of avocado, then ¼ of the tuna, and 1/3 cup quinoa.
Carefully turn the cup upside down to turn the stack out onto a plate.
Drizzle with 1 teaspoon soy sauce and sriracha mayonnaise.
Repeat with remaining ingredients.