Rinse the sushi rice thoroughly under cold water until the water runs clear. Cook the rice according to package instructions, about 18-20 minutes. Fold in rice vinegar and let cool slightly.

In a medium skillet, heat oil over medium heat. Add deveined shrimp, cooking for 3-4 minutes per side until pink and opaque. Remove from heat and toss with spicy mayo.

Slice cucumbers into thin rounds and dice the ripe avocado. Set everything aside for assembly.

Using a ring cutter or mold, layer sushi rice, seasoned shrimp, diced avocado, and cucumber slices. Finish with another layer of rice.

Drizzle spicy mayo over the top layer and sprinkle with sesame seeds and green onions for garnishing.

Carefully remove the molds and serve the stacks immediately to enjoy their freshness.