Cook rice: Wash and rinse rice until water runs clear. Drain well. Cook according to package instructions. Season with rice wine vinegar. Cover with a damp cloth to prevent drying. Allow to cool.

Prep all ingredients as listed above.

Prepare filling: Mix tuna, sriracha, sesame oil, and scallions in a bowl.

Roll sushi: Place nori shiny side down on a bamboo mat lined with plastic wrap. Spread rice evenly, sprinkle with sesame seeds, and arrange tuna mixture along bottom edge. Roll tightly, pressing gently to form a compact roll.

Make spicy mayo: Whisk mayonnaise, sriracha, and lime juice together in a small bowl.

Prepare matcha latte: Whisk matcha with hot water until smooth and foamy. Add milk, sweeten if desired, and serve over ice.

Slice rolls: Wet a sharp knife and cut each roll into 6–8 pieces, cleaning the blade between cuts. Top with spicy mayo or serve on the side.

Finish and serve: Serve sushi with soy sauce, wasabi, and pickled ginger (if using). Enjoy with an iced matcha latte and mochi ice cream.