I want to freeze onigiri with vegetarian or fish filling (ie. no chicken, pork, or red meat) in them, particularly tuna/mayo because I think it's more of a "meal" when you've got some stuffing in your afternoon tea time onigiri rather than just furikake ones. I'm too hungry by the afternoon to survive on rice alone, LOL! Is there any way to successfully freeze this kind? What fillings have you frozen successfully?