It's a lot easier than it looks. I made some earlier and decided to share
Onigiri is basically a riceball with filling. Mine is filled with some chicken I made yesterday. And I sprinkled black sesame seeds in the rice. (Mixing a couple tbsp rice vinegar into already cooked rice usually helps it stick better. But make sure you use short or medium grain rice. Warm rice is the best to make onigiri in my experience)
You need two small bowls. One lined with plastic to fill up with rice and meat. And the other with salt water to handle the rice ball after its compacted and shaped
Pack in some rice half way. Make a little well in it deep enough to add some chicken but not exposing any on the other side. And then cover with rice after you've added enough meat.
Close off the plastic and twist it. It looks like it's done but it's not. Now you have to cup it in both hands firmly to compact the rice together without squishing it everywhere (compacting the rice ball with your hands in an L shape will help to make it into a triangle. Or keep it round if you like)
You should end up with a triangle if I explained it well enough lol
Spray a pan with some nonstick oil. Cover your hands with some salt water, remove it from the plastic and lightly fry each side of the onigiri to set it and so it won't fall apart. And you're done! Usually onigiri has a strip of seaweed around the bottom or it's completely wrapped in seaweed, but I ran out so oh well. If you try this out please let me know! 😁