Rinse sushi rice under cold water until water runs clear. Place rice in a saucepan with water and bring to boil, then reduce heat and simmer for about 18-20 minutes until liquid is absorbed.

Transfer cooked rice to a large bowl and let cool slightly. Mix in rice vinegar, sugar, and salt while still warm. Fold gently with spatula.

Slice cucumber into thin, half-moon shapes and dice avocado. Arrange on a cutting board.

Layer serving bowls with seasoned sushi rice, topped with cucumber, avocado, and imitation crab or real crab meat.

Combine soy sauce and sriracha in a small bowl. Drizzle over assembled bowls.

Serve immediately for best taste and texture, optionally with pickled ginger.