Drain the tuna hard. Press it in the can lid or a sieve until no more water comes out. Watery tuna makes watery dressing, and that is the number one way this bowl goes wrong.
Whisk the soy sauce, sesame oil, rice vinegar, sugar, and ginger in a medium bowl.
Add the tuna in big pieces and fold gently two or three times. You want chunks coated in dressing, not tuna salad. Let it sit 5 minutes to absorb.
Stir the mayonnaise and sriracha together. Thin with a teaspoon of water until it drizzles off a spoon.
Divide the rice between four bowls. Arrange the tuna, edamame, avocado, cucumber, and carrot on top in sections.
Drizzle with the sriracha mayo, then finish with scallions and sesame seeds.