First you will need: (starting from top left) Soy Sauce, Sesame Oil, a bowl of rice, salt, a warm bowl of water, Nori (seaweed, make sure its the kind you use for sushi!), a big plate, and Tuna! Making tuna sushi rolls (or any type of sushi for that matter) requires use of your hands - So make sure they're clean!
After opening and draining the Tuna from it's can, put it into a bowl, add about a table spoon of soy sauce, and sesame oil. It all depends on how much flavor/calories you want. I personally like Sesame Oil, so I put more. (If you don't like Soy Sauce or Sesame Oil, you could substitute mayonaise also)
Next, take the warm bowl of water, and pour about a teaspoon of salt in it, and gently mix.
This step, and the step above is to make it easier for you to handle the rice. Wet the palm of your hand (and fingers) in the salted water. This is so the rice won't stick to your hands so much.
Take out a piece of nori and place it on the plate. Then put about a scoop of rice at the end. Then spread the rice out so it covers the bottom half. Don't be afraid to use your hands!
Next add the tuna neatly in the middle of the rice. (as you can see I didn't put that much rice, but thats only because I personally less rice more tuna. But you can make yours different ^_^
Next, roll it up! Continue doing this step until you've used up all the tuna you made.
When you're finished rolling all of them up, they should look something like this. If you're super hungry, you could go ahead and start eating it now haha (I usually do lol). But as you can see, I've already starting cutting them in half. You can them into 6 pieces!
Theeeeennn TADAAA! You now have nice tuna sushi rolls great to bring as snacks to places ^_^ (I meant to take pictures of the actual finished product when I was finish cutting them up, but I got the munchies and forgot to take pictures. Good thing I remembered when I still had a few left!) Enjoy ^-^<3