01 - Rinse sushi rice under cold water until clear. Combine with water in a saucepan, bring to a boil. Cover, reduce heat, and simmer for 15 minutes. Remove from heat and let steam, covered, for 10 minutes.
02 - Mix rice vinegar, sugar, and salt in a small bowl. Gently fold into cooked rice. Allow to cool to room temperature.
03 - Whisk soy sauce, sesame oil, rice vinegar, sriracha, and honey together. Toss diced tuna in marinade and refrigerate for 10 to 15 minutes.
04 - Combine mayonnaise, sriracha, and lemon juice. Adjust sriracha for desired heat level.
05 - Slice avocado, julienne cucumber, shred carrot, cut nori into strips, and thinly slice scallions.
06 - Divide sushi rice evenly into four bowls. Top with marinated tuna, avocado, cucumber, carrot, nori strips, toasted sesame seeds, and scallions.
07 - Drizzle bowls with spicy mayo and garnish with pickled ginger if desired. Serve immediately.