01 - Rinse sushi rice under cold running water, agitating gently, until the water runs completely clear. Drain thoroughly.
02 - Combine rinsed rice and water in a medium saucepan. Bring to a rolling boil, then cover with a tight-fitting lid, reduce heat to low, and simmer for 15 minutes. Remove from heat and let stand, covered, for 10 minutes undisturbed.
03 - While the rice rests, whisk together rice vinegar, sugar, and salt in a small bowl until fully dissolved. Gently fold the mixture into the warm rice using a rice paddle, taking care not to mash the grains. Allow the rice to cool slightly before assembling.
04 - Shred the crab sticks into fine pieces. Dice the avocado, julienne the cucumber into thin matchsticks, slice the nori sheets into narrow strips, and chop the pickled ginger and green onion.
05 - Stir together mayonnaise and sriracha in a small bowl until evenly combined. Adjust the heat level to taste.
06 - Divide the seasoned rice evenly among four bowls. Arrange shredded crab, diced avocado, julienned cucumber, nori strips, and pickled ginger over the rice in sections.
07 - Drizzle each bowl with spicy mayo and soy sauce. Finish with a generous sprinkle of toasted sesame seeds and sliced green onion. Serve immediately with additional soy sauce on the side.