Step 1

Chop the scallions, reserving some of the greens for garnish.

Step 2

Slice the tuna into thin strips and then turn the strips 90 degrees and chop it up. If you want your spicy tuna chunky, you can stop here, or you can continue to chop the tuna up with your knife until the pieces are smaller. I usually add the scallion stems in here and chop them up together with the tuna.

Step 3

Transfer the chopped tuna to a bowl, and add the sriracha, soy sauce, sugar, sesame oil, and tobiko, and stir everything together until mixed. Cover and keep the mixture refrigerated until you're ready to use it.

Step 4

Make some Tezu by adding a few tablespoons of rice vinegar to a small bowl of water.

Step 5

For the Gunkan, you want to cut the nori according to the diagram in the headnotes above.

Step 6

Wet your hands with the tezu and grab about 2 tablespoons of rice. Gently press it into a rectangle with your fingers, but don't smash the individual grains of rice.

Step 7

Wrap each rectangle of rice with the strips of nori you cut for the gunkan.

Step 8

Press the center of the rice to make the rice fill out the nori wrapper.

Step 9

Spoon some spicy tuna into each cup of nori. Garnish with scallion greens.

Step 10

For Hosomaki, the full sheets of nori should be cut in half according to the diagram above.

Step 11

Place the nori at the bottom edge of a sushi mat with the shiny side down.

Step 12

Wet your hands in the Tezu and grab a small handful of rice. Place the rice in a line along the nori's top edge working from one side to the other. Be sure to leave a thin margin of nori at the top.

Step 13

Wet your hands again if needed and spread the rice to the bottom edge of the nori using a picking and pressing motion. Don't smash or smear the rice.

Step 14

Spread a thin line of spicy tuna in the lower half of the rice from one side to the other.

Step 15

To roll the spicy tuna hosomaki, use the mat to flip the bottom edge up and over the filling and make sure this edge meets the rice's top edge.

Step 16

Pull the edge of the mat away from the nori and push the back of the mat forward, so the seam rolls to the bottom.

Step 17

Use your fingers to press 3 sides of the roll against the cutting board to give the roll its shape.

Step 18

See the headnotes or watch the video for instruction on cutting a roll.

Step 19

For Uramaki, the size of the nori and process is similar, but you need to use a sushi mat that is lined with plastic wrap, or the rice will stick to the mat.

Step 20

Place a sheet of nori at the bottom edge of the mat and spread a handful of rice along the nori's top edge. There is no need to leave a border for uramaki, so you will need to use a little more rice than for hosomaki.

Step 21

Spread the rice down to the nori's bottom edge in a thin uniform layer, being careful not to smash the rice.

Step 22

Sprinkle some black sesame seeds onto the rice.

Step 23

Flip the rice over so the nori is facing up, and lay a cucumber strip in the bottom half of the nori.

Step 24

Spread a line of spicy tuna from one side to the other.

Step 25

Flip the bottom edge of the mat up and over the filling until the rice makes contact with the nori on the other side.

Step 26

Pull the edge of the mat away from the rice and press the back of the mat to roll the seam to the bottom.

Step 27

Press the top, sides, and bottom of the roll using the mat to give the roll its shape, but do not squeeze it too hard.

Step 28

Check the headnotes for instructions on cutting the spicy tuna roll.