Spicy Tuna Hand Roll

Name: Spicy Tuna Hand Roll
Ingredients: 1 cup rice; 1 1/4 cup water; 1 tablespoon sugar; 1 teaspoon vegetable oil; 2 tablespoons rice wine vinegar; 2 tablespoons mayonnaise or kewpie; 1-2 teaspoons Sriracha (depending on spice tolerance); 1/2 pound sushi-grade ahi tuna, cut into a small dice; 1/4 teaspoon kosher salt (more to taste); 1/4 teaspoon black sesame seeds; 6 toasted nori sheets; 1 cucumber, julienned; Handful of Asian mix sprouts; 2 tablespoons ponzu sauce; 2 tablespoons soy sauce; sesame seeds or green onion as garnish