Instructions

1. Cut or mince raw tuna into small cubes and set aside.

2. Peel the cucumber and cut into small, thin match stick strips. Set aside.

3. Combine Japanese Kewpie mayonnaise with Sriracha sauce in a bowl, to taste. Sriracha sauce is spicy, so start with a small amount and add more depending on how spicy you want the rolls to be.

4. Add the chopped tuna to the spicy sauce and stir until it's thoroughly coated.

5. Lay out the bamboo sushi mat on a flat work surface, so that the lines of bamboo run across horizontally. Lay a piece of plastic wrap on top of the surface of the mat to protect it. Place a small bowl of warm water nearby.

6. Tear a sheet of nori seaweed into two and place one half sheet on the bamboot mat, with the sheet's smooth, shiny side down and the rough side up. The rough side is used to grab the rice.

7. Moisten your fingertips in the water and grab enough rice to form a small ball. Place the rice ball in the center of the seaweed sheet. Spread the rice so that it covers the entire sheet with a thin layer, pressing down gently with your fingers as you go. If rice sticks to your hands, moisten your hands with more water. You can also use a rubber spatula instead, to make a thin, even layer.

8. Flip the seaweed over so that the rice is facing down.

9. Place a line of the spicy tuna mixture lengthwise across the bottom edge of what is now the top of the seaweed sheet, using a spoon. Putting the tuna on the bottom will ensure it's centered in the middle as you roll it up.

10. Add a layer of the thinly-sliced cucumber strips on top of the tuna. Sprinkle with the panko bread crumbs. For gluten-free spicy tuna rolls, omit the bread crumbs. The cucumber and the crumbs are what give the rolls their crunchy texture.

11. Lift the bottom edge of the bamboo mat and slowly flip it away from you. Gradually roll the mat toward the top until it forms a cylinder. As you roll, the seaweed sheet, with the rice and tuna, will also roll up inside the mat. Tuck the leading edge of the seaweed sheet under, if necessary.

12. Remove the mat to release the tuna roll. Sprinkle sesame seeds on top of the rice, then let the sushi roll rest for a couple minutes with the open edge of the seaweed face down.

13. Transfer the roll to a cutting board. Wet a long, sharp serrated knife with a little water.

14. Cut the roll in half using long sawing strokes. Don't press down with the knife. Put the two sushi roll halves next to each other and cut through them two additional times, creating six pieces. Wet the blade as needed in-between cuttings, or wipe the blade with a wet rag.

15. Garnish the spicy tuna roll pieces with more panko crumbs, sesame seeds or scallions as desired.