Maki of Just Bento & Just Hungry has a bunch of articles on onigiri, but the best place to start is her onigiri FAQ (http://justbento.com/handbook/bento-basics/onigiri-omusubi-faq
One of the links is to the Cooking Cute blog’s instructions on using a mold like the one we sent you (http://www.cookingcute.com/onigiri_with_filling.htm
). My instructions are pretty much the same as theirs.
Make some rice. You need to be using Japanese style short grain rice, sometimes labeled as sushi rice, otherwise it won’t stick right.
Make the onigiri as soon as the rice is done. It will be hot, but since you’re using a mold it should be ok (I’ve made them the traditional way by hand and it’s kinda painful with hot rice).
Wet the mold and fill about half way with rice. Do not pack the rice in.
Make a little divot in the center for filling and put something in it. I’m a traditionalist and use umiboshi or umiboshi paste. If you’re using umiboshi you’ll probably want to remove the pit first: not only is it large, but sometimes it has a little point on top that likes to jab into lips.
If you buy umiboshi paste in a squeeze bottle you can cheat and inject it in after making a plain onigiri.
Fill the mold the rest of the way with rice, then press down the lid.
Remove the lid, turn the mold over, and give it a good shake to release the onigiri. I think the style of mold we gave you has a flap on the back you can push on to help release the onigiri if necessary.
Re-wet the mold and lid before making the next one.
Sprinkle a little salt on the onigiri and, if you’re going to eat it immediately, put a strip of nori on it. I don’t recommend putting nori on the onigiri until you’re about to eat it, otherwise I find it gets mushy, so if you’re packing for a snack later I keep the seaweed in a separate bag until eating time.
That’s pretty much it.