Look at any of the flavor profiles here at
g'day gourmet I've tried all of them except the lemon-pepper one. Amazingly, they were all good with the tuna. I would think they'd all be doable at home with some spices or sauces, a little oil to carry the flavors and unflavored tuna - especially if it could sit for sometime to take up the flavors. You can always drain off any excess oil from your experiment.