In a medium bowl, whisk together ¼ cup of mayonnaise and 2 tablespoons of sriracha until smooth and creamy. Gently fold in 8 ounces of chopped imitation crab, ensuring every piece is well-coated. Allow the mixture to sit for 5 minutes.

Rinse 1 cup of short-grain rice under cold water until it runs clear. In a rice cooker, combine the rinsed rice with 1¼ cups of water and cook according to the manufacturer's instructions. Let the rice steam for an additional 10 minutes.

Divide the cooked rice evenly into two serving bowls, creating a well in the center of each bowl.

Generously spoon the spicy crab mixture into the wells, allowing it to cascade slightly over the rice.

Sprinkle sesame seeds and sliced green onions over the top of the crab mixture in each bowl.

Serve each bowl with a small dish of soy sauce on the side, along with optional wasabi and pickled ginger.