Rinse the rice under cold water until clear. Cook rice in a rice cooker with water for about 20 minutes. Mix in vinegar, sugar, and salt while warm and cool to room temperature.

While rice cools, shred crab sticks, slice avocado, and julienne cucumber. Prepare fillings on a plate.

Place nori on sushi mat, spread rice, leaving a border. Ensure even distribution.

Flip nori so rice side is down. Layer crab, avocado, and cucumber on lower third.

Roll tightly from the edge closest to you, tucking in the filling as you go. Seal the roll with wet nori edge.

Top with mayonnaise or sriracha and sprinkle with crispy toppings. Slice into pieces with a sharp knife.

Serve sliced rolls on a platter with soy sauce for dipping.