This recipe is especially good for those who are afraid to put fish on the grill, thinking that it will stick to it or not be sturdy enough to be cooked this way. That is not the case of tuna. The fact that you cook it as a roast, without slicing it into steaks, ensures the tenderness and moisture inside the meat. Its simply delicious! It goes great with a fresh greens salad with balsamic vinaigrette.