Check the related link.

The video will tell you how to make onigiri with nori and tuna.

Onigiri - 2010 was released on:

USA: 5 May 2010 (Academy of Motion Picture Arts and Sciences)

It all depends on your guests. If you have friends who are knowledgeable of Japanese food, or who are just adventurous eaters, its a great idea, but if you have a lot of picky eaters you may end up with a plate of Onigiri to finish alone. A happy medium might be to fill the onigiri with something pleasant to picky eaters and onigiri lovers like. Maybe chicken as opposed to pickled plum.

If you mean Onigiri then It can mean 2 things what I know.

Onigiri = Rice Ball, A famous Japanese food thingy.

Onigiri = Demon Bull, Zoro from one piece's attack, maybe it's badly translated but still :)

Hope that gave you your answer!