Onigiri

Cute like sugar cookies, without actually being a dessert.  
We like it as an afternoon snack or in a packed lunch.

Leftover rice, about 2 cups
2 tablespoons of rice vinegar
1/4 teaspoon salt
1/4 teaspoon sugar

I spread the rice out on a plate.
I mix the vinegar, salt, and sugar to make a dressing.
I sprinkle the dressing on the rice.

I pack the rice into molds to make shapes, using my rice paddle to push the rice into the mold and level it.  I've got a little onigiri mold with three little shapes, which I bought in a japanese market a few years back.  Before that I used to just mold with a 1/4 cup measure.

Real onigiri would have something hidden in the middle, like pickled plum.  I've never met a pickled plum.  We usually just make them plain--haven't come up with a filling that interests any of us.

Do you make onigiri?  Is your vinegar-salt-sugar dressing different?  Do you put a little filling in the middle?