Rinse rice in a strainer until water runs clear. Combine rinsed rice and water in a medium saucepan; bring to a boil. Reduce heat to low, cover, and cook until rice is tender and water is absorbed.

Combine rice vinegar, sugar, and salt in a small saucepan over low heat; stir until sugar is dissolved. Pour over rice; stir until rice cools and looks dry.

Preheat the oven to 400°F (200°C). Grease a baking sheet with cooking spray. Arrange shrimp tempura on the prepared baking sheet.

Bake shrimp in the preheated oven until golden and crispy, about 6 minutes per side. Cut the tails off of 4 tempura shrimp.

Cover a bamboo sushi rolling mat with plastic wrap. Lay 1 nori sheet, shiny-side down, on the plastic wrap. Spread 1 cup rice over nori using moistened fingers, leaving a 1/3-inch border. Flip nori so rice is facing the mat.

Arrange imitation crabmeat and cucumber along the bottom edge of nori. Place 2 tail-off shrimp in the center of nori. Place 2 tail-on shrimp on the end so that the tails extend over the sides of nori. Lift the edge of the mat and roll up nori into a tight log around filling.