Tuna Mayo Sushi Sandwich Ingredients: 1 serving 4 oz cooked white rice 1 Tbsp sushi vinegar 2 leaves of green leaf lettuce 1/8 yellow bell pepper, sliced 1 oz seedless cucumber, thinly sliced 1 sheet sushi nori seaweed 2 Tbsp Kewpie Mayonnaise 1 Tbsp canned tuna Directions In a small bowl,.