Ingredients
2 large cucumbers 
1 cup cooked sushi rice 
1 tbsp rice vinegar
1/2 tsp sugar
1/4 tsp salt
4 oz fresh sushi-grade fish (like salmon or tuna) or cooked shrimp 
1/2 avocado, diced 
1/2 small carrot, julienned 
1/2 small cucumber, julienned
Soy sauce, for dipping 
Optional toppings: sesame seeds, nori strips, pickled ginger
Instructions
Prepare the Cucumbers: Slice the cucumbers into thick rounds (about 1 inch tall). Using a melon baller or small spoon, gently scoop out the center of each cucumber round, being careful not to go all the way through. You want to create a little cup.
Season the Rice: In a bowl, mix the rice vinegar, sugar, and salt with the cooked sushi rice. Stir until the rice is evenly seasoned.
Fill the Cups: Spoon a small amount of sushi rice into each cucumber cup, pressing it down lightly. 
Top It Off: Add a piece of fish or shrimp on top of the rice. Then, garnish with a bit of diced avocado, julienned carrot, and cucumber. You can get creative with your toppings here—go with what you love! 
Serve: Sprinkle sesame seeds and nori strips on top if you like, and serve with soy sauce for dipping.
Enjoy your fresh and delicious sushi in a cucumber cup!