How to Make It
Heat rice according to package directions.
Arrange nori sheets, rough side up, on a work surface so they're diamond-shaped. Pat 1/4 cup rice into a 3 1/2-inch square the center of each nori sheet. Spread 2 tablespoons cream cheese onto each rice square; sprinkle each with 1 tablespoon onions. Top each with even layers of 1 ounce salmon, 1/4 cup cucumber, and 1/4 cup carrots; pat 1/4 cup rice over each stack. Bring 2 side corners of nori over filling; press gently to seal. Fold top and bottom corners over filling; press gently to seal.
Wrap sandwiches in wax paper or parchment paper to help them hold their shape; cut in half.