I made this because I promised someone on the board that I would, but I know that sushi polymer clay tutorials are already abundant in number on the internet so mine is pretty redundant lol. Still I felt like I should do what I said i'd do so here it is:
Nigiri Sushi tutorial:
1. You'll need red, orange and white clay, plus a sharp blade for clean cutting and a sharp ended tool like a toothpick. Optional tools include liquid sculpey and translucent clay.
2. Grab your white clay and shape it into a rectangle. To do this, roll the clay into a sphere and press down at the top to create an oval. Then push the four sides in to make the sides. This will be the rice that goes under the tuna in nigiri. If you mix half the white with half translucent clay it might look more realistic because rice is not opaque white.
3. Mix the orange and red clays roughly in the ratios shown. For one chunk of clay, mix half red and half orange, and then mix 3/4 orange with 1/4 red.
4. This is what you should get.
5. (There's a picture missing from this step, i'm so sorry!). Divide the mixed clays into six parts (three for each colour). Flatten the clumps into disks and stack them alternating like shown in the picture. To create a more realistic effect have some disks that are fat in the middle and some very thin disks, otherwise you will end up with uniformly striped tuna.
6. (Sorry about the blurriness of this picture!) Take your tissue blade and slide off the sides of your tuna so that you have a nice stripey rectangular block of tuna. It should end up looking like the second picture.
7. Tip your tuna over and flatten either with your hand or your rolling pin. Also try to shape the ends of the tuna to be slightly rounded at the corners. I suggest you do this step carefully because you can't unflatten the tuna in case it is too flat for your liking.
8. If you have liquid sculpey, apply some to the underside of your tuna and press onto your rice. If not, I suggest you bake the rice and tuna separately and glue them together once they are baked so that they don't separate. You can be finished here or...
9. ... if you want your rice more realistic, take a pointed tool and poke randomly at the white part all around.
10. Voila. Tuna nigiri sushi.
I tried to make a tutorial of a sushi cane (like the normal roll up sushi) but it was a total fail lol. I tried three times and i'm just not a cane person. There's a tutorial here (not mine!) http://chat-noir.deviantart.com/art/Sushi-Cane-Tutorial-58865159