What methods can be used to cook Skipjack tuna other than frying it in oil? First of all I must say that I'm not a fish person but a red meat person. However I'm currently on a diet and as such I've been looking for different ways to properly cook Tuna with low fat. 

I know there are my recipes out there, I'm not looking for an specific one but rather a short summary of the methods used to cook fish without requiring much expertise and can be done quick and without much equipment. Therefore is there anyone who can help me with this?

Please don't say just boiling it in water or putting in the oven for who knows how long. I must add that I do not have access to an oven so the suggestion which would help me the most is one which does refrain from using it.

Maybe this can work but is not what I'm looking for. I'm aiming at something which has proved over the time to be easy to do and use little or almost no oil.
A few suggestions:


Raw. If your fish is great quality and very fresh, and you have  a good sharp knife (just look up the way to cut it for the nicest texture)
Ceviche. This cooks (denatures) the fish with acid, rather than heat. Lots of recipes out there for great marinades, some with no added oil at all.
Seared. You only need to add rub enough oil into the surface of the fish to prevent it from sticking, to a hot griddle or flat pan.
Steamed. Often with aromatics. In a bowl to catch the juices, or wrapped in a loose but well-sealed package of foil or greaseproof paper (en papillote).


Gently poached in good oil is very nice, but I don't think that would meet your dietary requirements!

En papillote Is often done in quite a hot oven: the package enforces steaming inside; the fish isn't exposed to fierce heat.

All of these methods will be enhanced by your choice of recipe for dipping sauces, dressings, marinades,  sides, etc. There's no difficult technique in most of them. The lucky thing about good fish is.. the less you do to it, the better it is. (Almost). Look up the methods, and you'll find the recipes.

The only real danger is overcooking. You'll have to get to know your preferred doneness.