Canned Tuna Rice Bowl

Name: Canned Tuna Rice Bowl
Ingredients: ¾ cup kimchi , coarsely chopped; 3 tablespoons mayonnaise , divided; 2 tablespoons seasoned rice vinegar , divided; 3 teaspoons toasted sesame oil , divided; ½ teaspoon salt , divided; 2 (5-ounce) cans no-salt-added water-packed white tuna , drained and flaked; 1½ teaspoons Sriracha; 2 small Persian cucumbers , thinly sliced (about 1 cup ); 1 teaspoon grated fresh ginger; 2 cups hot cooked brown rice; 1 medium firm, ripe avocado , chopped ( 1 cup ); 1 teaspoon toasted black or white sesame seeds; 1 medium scallion , thinly sliced ( 2 tablespoons ); 12 (4-inch) sheets nori