Follow these simple instructions to prepare your Spicy Shrimp Sushi Stacks:

1. Cook the Sushi Rice: Rinse the sushi rice under cold water until the water runs clear. Combine with water in a rice cooker according to the device instructions, or cook on the stovetop until tender and sticky.

2. Season the Rice: In a small saucepan, heat rice vinegar, sugar, and salt until dissolved. Once the rice is cooked, transfer it to a large bowl and gently fold in the vinegar mixture. Let it cool.

3. Prepare the Shrimp: In a skillet over medium heat, add a little oil and cook the shrimp until they turn pink and opaque, about 3-4 minutes per side. Remove from heat and let cool slightly.

4. Make Spicy Mayo: In a small bowl, mix mayonnaise and Sriracha sauce until combined. Adjust the amount of Sriracha according to your spice preference.

5. Assemble the Stacks: In a small cup or mold, layer the sushi rice, followed by shrimp, avocado slices, and julienned cucumber. Press gently to compact each layer.

6. Flip and Mold: Place a serving plate on top of the cup or mold and invert to remove the stack. Carefully lift the mold away.

7. Garnish: Drizzle spicy mayo on top of each stack and sprinkle with sesame seeds and sliced green onions.

8. Repeat: Continue to assemble the remaining stacks until all ingredients are used.

These steps will lead you to a delightful dozen or more of these incredible sushi stacks!