01 - Place sushi rice in a fine-mesh strainer and rinse under cold running water, gently swirling with your hand, until the water runs completely clear. Drain thoroughly.
02 - Transfer rinsed rice and 2 cups of water to a medium saucepan. Bring to a rolling boil over medium-high heat, then cover tightly with a 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. Transfer the warm rice to a large bowl, drizzle the vinegar mixture over top, and gently fold in with a rice paddle using slicing motions. Avoid mashing the grains. Allow the rice to cool slightly.
04 - Shred the imitation crab sticks into thin pieces. Dice the avocado, julienne the cucumber into thin matchsticks, slice the nori sheets into thin strips, thinly slice the green onion, and roughly chop the pickled ginger.
05 - In a small bowl, stir together the mayonnaise and sriracha until smooth and well combined. Adjust the sriracha amount to taste.
06 - Divide the seasoned sushi rice evenly among four serving bowls. Arrange the shredded crab, diced avocado, julienned cucumber, nori strips, and pickled ginger in sections over each bowl of rice.
07 - Drizzle each bowl with spicy mayo and soy sauce. Sprinkle generously with toasted sesame seeds and sliced green onions. Serve immediately with additional soy sauce on the side.