Rinse rice under cold water until clear.
Cook rice in a cooker or pot.
Mix vinegar, sugar, and salt.
Stir into warm rice gently.
Slice cucumber, avocado, and carrots thin.
Cut nori sheets into thin strips.
Arrange rice in a large bowl.
Place shrimp or salmon on top.
Add avocado, cucumber, and carrots neatly.
Drizzle Yum Yum sauce over bowl.
Sprinkle sesame seeds on top.
Garnish with nori strips.
Add soy sauce and sriracha if desired.
Serve fresh with chopsticks or spoon.