Rare or Well you need to know the best method for grilling Tuna.
The grill offers you two ways of preparing tuna. One method is to grill it over a high heat for about 4 to 5 minutes per side until it is cooked through. The other method is to grill it over a very high heat for about 1 to 2 minutes per side. The first method is a much more traditional way of preparing fish on the grill. The second method is to simply sear the outside of the fish and leave the middle pretty much raw. I know that probably scares more than a few people, but sear tuna is one of my favorites. Okay, we'll get to that one later.
Tuna is a very lean fish and tends to dry out quickly on the grill. While marinating and applying oil to the fish will help reduce this, if you cook tuna beyond medium rare it will be dry. To combat this on the plate you will want to serve grilled tuna with a sauce or some kind of salsa. If you are going to serve the tuna with a topping like a sauce then you don't
need to do a lot to the fish. Simply brushing the tuna with some oil, seasoning light with salt and pepper will give you a great piece of fish. The topping will provide added flavor and moisture to the meal. Otherwise you can marinade the tuna in a light marinate. Anything with a lot of acid will tend to cook the fish before it hits the grill so the marinade you use should be pretty mild. Go with some olive oil, herbs, spice and a small amount of lemon juice or flavored vinegar.