Rice has multiple uses

Onigiri aka Rice Balls
3 cups rice, cooked

The trick with this receipe is how you wash your rice. Short grain rice has a lot of starch that should be washed out before you cook it. If the wash water remain just a little bit milky, the rice will be stickier than normal. Cook the rice whatever way you have available. You will be making your rice ball while the rice is still warm from cooking. If you rinse your hands in salty water, you can mold the rice balls without having it stick to your hands. You scoop up an amount that you can comfortable compress in your hands. While squeezing the rice together, you can mold it into whatever shape suits your fancy, like disks, barrels, or triangles. If you are using a filling, make a cavity in the rice you've just pulled from your cooking pot and stick a small amount of filling inside. You don't want too much filling for several reasons, it will escape as you compress it or the rice ball won't stay together because of too much filling. You can just season the rice before making your ball. There are several available at your local Japanese supermarket, many of them fish flavoured. Personally, I looking for the ones that has the word "Ume" among the first few ingredients. That means it's a pickled plum flavored seasoning.

For Fillings try: tuna, pickled plum, pickled diakon radish, leftover chinese food (without the rice, obviously), leftover beef stew, leftover stir fry, etc.

Note: Rice balls can be eaten hot or cold. I warm them up by steaming them but microwaving them should work just as well.