Rinse sushi rice under cold water until it runs clear. Cook according to package instructions, about 20 minutes. Let it sit covered for 10 minutes, season, and cool.

Combine tempura batter mix with ice-cold water in a bowl, stirring gently. Heat oil to 350°F (175°C).

Dip shrimp in tempura batter and fry in hot oil for 2–3 minutes until golden brown. Remove and drain on paper towels.

On a nori sheet, spread sushi rice, leaving a border. Place tempura shrimp, avocado slices, and cucumber.

Roll tightly using the bamboo mat, sealing the edge with water. Press gently to shape.

Slice the roll into 1-inch pieces with a wet, sharp knife for clean edges.

Serve the rolls on a platter with soy sauce for dipping and optional garnishes.