Place your shrimp in a pot with cold water. Bring to a boil and cook the shrimp for about 2 minutes. Remove them from the pot and transfer them immediately to a bowl filled with cold water and ice. Wait 5 minutes and then chop them up.
Cucumber Salad:
In a medium bowl, toss the cucumber, vinegar, oil, sugar and salt.
Toast your sesame seeds in a small pan on medium low heat tossing constantly. Don't walk away, they burn easily. Mix them into the salad.
Assembly:
Place the cooked shrimp in a dish and spread it out flat. Spread out the chopped shrimp on top. Drizzle with soy sauce, Sriracha and kewpie mayo as desired. Add the scallions and mix everything with a fork to combine. Add on your avocado and salad and scoop up the goods with the nori paper squares and eat like sushi.
Notes
You can use any type of rice.For the Cucumber Salad: you can use white wine vinegar instead of rice vinegar. You can use olive oil instead of sesame oil.Regular mayonnaise works here too.