How to Make It
In a fine strainer, rinse the rice with cold running water, until water runs clear. Pour rice into pot with 2 cups cold water; let sit 30 minutes.
Bring rice to a boil over medium-high heat; immediately turn heat to low, and cover. Cook 10 minutes, remove from heat and let sit, covered, 15 minutes. In a small saucepan, dissolve the sugar and salt in the rice vinegar over a low flame. Pour evenly over rice and fold gently with a wooden spoon to mix. Leave rice in front of a fan, or fan with a piece of cardboard for 15 minutes or until rice is just above room temperature.
Place tuna in freezer for 20 minutes or until semi-frozen. Cut tuna into ¼-inch cubes.
Whisk together mayonnaise, sriracha, sesame oil, lemon juice, and honey in a small bowl. Reserve 2 Tbsp. sauce, then stir in chopped tuna to larger portion of spicy mayo.
Line a sushi mat with plastic wrap. Pat room temperature rice in a thin single layer onto sushi mat, leaving a ½-inch border on all sides. Place 1 sheet of nori on top of rice, then place 6 cucumber matchsticks crosswise in a line on the bottom third of the nori, followed by 4 slices of avocado, and 2-3 tablespoons tuna mixture.
Fold sushi mat over and roll sushi-style, using the mat to hold and shape your sushi roll. Unroll sushi mat and slice roll into 8-10 slices, discarding edge pieces.
Drizzle with reserved spicy mayo mixture, and garnish with fried okra.