01 - Rinse sushi rice under cold water until water runs clear. Combine rice and water in a saucepan, bring to a boil, reduce heat, cover, and simmer for 15 minutes. Remove from heat and let stand, covered, for 10 minutes. Whisk together rice vinegar, sugar, and salt; fold gently into the warm rice. Allow to cool slightly before assembling.
02 - In a mixing bowl, combine soy sauce, sesame oil, Sriracha, honey, green onion, and sesame seeds. Add diced tuna and toss gently to coat evenly. Cover and refrigerate for at least 10 minutes to develop flavors.
03 - Dice mango and avocado into uniform cubes. Thinly slice cucumber and radishes. Julienne the carrot into matchstick strips. Keep all vegetables chilled until ready to assemble.
04 - Divide seasoned rice among four serving bowls. Arrange spicy tuna, mango, avocado, cucumber, carrot, and radishes in sections over the rice for visual appeal.
05 - Drizzle spicy mayo generously over each bowl. Sprinkle with roasted seaweed strips, additional sesame seeds, pickled ginger, and cilantro. Serve immediately while fish is fresh and rice remains slightly warm.