In a medium bowl, whisk together 1/2 cup of mayonnaise and 2 tablespoons of sriracha until smooth. Gently fold in 8 ounces of chopped imitation crab until fully coated in the creamy sauce. Set aside.

Rinse 1 cup of sushi rice under cold water until the water runs clear. Cook the rice according to package instructions, typically bringing it to a boil and then reducing to simmer for about 15 minutes. Let it sit covered for an additional 10 minutes.

Fluff the rice with a fork and divide it into serving bowls while warm. Spoon the prepared crab mixture over the rice in each bowl.

Drizzle soy sauce over the crab mixture in each bowl for added umami. Sprinkle with toasted sesame seeds and top with chopped green onions.

Serve with wasabi and pickled ginger on the side, allowing guests to customize their heat levels.