Rinse and cook the rice

• Rinse the sushi rice under cold water until the water runs clear.
• Cook the rice in a rice cooker with the water and the kombu.

Make the sushi vinegar

• Combine the rice vinegar, sugar and salt.
• Warm in the microwave until the sugar and salt dissolve.

Season and press the rice

• Pour the vinegar mixture over the hot rice and mix until fully incorporated.
• Spread the rice evenly on a plastic-lined baking tray, cover with plastic wrap and press with a second tray on top.
• Chill in the fridge until solidified.

Prepare the spicy tuna

• Finely mince the tuna and slice the scallions and chives.
• Combine the tuna with the scallions, grated ginger, soy sauce, yuzu juice, sesame oil, Japanese mayonnaise, sriracha and salt.
• Mix well and keep in the fridge.

Cut and deep fry the rice

• Remove the rice from the tray and cut into your preferred shape.
• Deep fry at 190 °C until golden brown and crispy, adding the rice pieces in 30 second intervals so they don't stick together.

Assemble and serve

• Season the crispy rice with salt.
• Top with the spicy tuna and garnish with chives.