Does anybody have experience with Onigiri?

[MM1988]

 

These rice balls seem like the perfect dinner for during the week. And you can fill them with whatever you like. 

My question would be what would be a good healthy filling for these. And how long can you store them?

Obviously you cant fill them with salmon and keep them 5 days in the fridge but maybe it would work with something else.

I could also prepare them on monday and wednesday for the following 3 and 2 days. 

What could work best? Making them everyday after work seems to be a hassle. I have stored rice in the fridge airtight for 5 days and saw no problem, I guess the problem would be the filling.