Rinse the rice thoroughly and cook it in a rice cooker.
Once the rice is done, stir in rice vinegar, sugar, and salt while it’s still warm. Mix well and let it cool to room temperature.
Line a container with plastic wrap. Press the rice firmly into the container to form an even layer.
Cover and freeze for at least 1 hour until solid.
Dice the sushi-grade tuna into small pieces and place them in a bowl.
Add Kewpie mayo, sriracha (to taste), and chopped green onions. Mix and refrigerate until ready to use.
Remove the rice from the freezer and cut it into bite-sized squares.
Fry rice squares for 3–4 minutes per side, or until golden brown and crispy.
Drain on a wire rack/
Spoon the spicy tuna mixture on top of each crispy rice square.
Top with a slice of jalapeño for extra heat.
Serve and Enjoy!