Make cauliflower rice by placing florets in a food processor. Pulse until finely chopped.
Combine cauliflower rice and sesame oil. Stir and set aside.
In a small bowl, gently mash avocado until slightly chunky. Stir in cilantro.
In a separate bowl, toss shrimp in Coconut Aminos to coat.
Mix mayonnaise with Sriracha sauce.
Using a one cup measuring scoop, layer 1/4 cup of cucumber, spread avocado, shrimp, and finished cauliflower rice. Gently press into cup.
Set a plate on top,then flip the measuring cup over. Lightly tap on the top to release.
Top each shrimp stack with spicy mayo, sesame seeds, and black pepper.