Rinse the sushi rice under cold water until the water runs clear

In a medium pot, combine the rinsed rice and water. Bring to a boil, then reduce the heat to low, cover, and simmer for 15-20 minutes, or until the rice is tender and the water is absorbed

In a small bowl, mix the rice vinegar, sugar, and salt. Microwave for 15-20 seconds to dissolve the sugar

Once the rice is cooked, transfer it to a large bowl and gently fold in the vinegar mixture. Let the rice cool slightly

While the rice is still warm, shape it into small rectangular blocks (about 2 inches long and 1 inch thick). Pro tip: Wet your hands with water to prevent sticking.

Heat the vegetable oil in a nonstick skillet over medium-high heat. Carefully place the rice blocks in the pan and cook for 2-3 minutes on each side, or until golden and crispy. Transfer to a paper towel-lined plate to drain

In a medium bowl, combine the chopped tuna, mayonnaise, sriracha, soy sauce, sesame oil, green onion, and sesame seeds. Mix gently until well combined. Taste and adjust the seasoning if needed

Place a spoonful of the spicy tuna mixture on top of each crispy rice block

Drizzle with spicy mayo and garnish with green onions, jalapeños, and sesame seeds.