Grilled Yellowfin Tuna with Lemon and Garlic

Recipe from the Harris Teeter's Fresh Catch newsletter
Put the fish in a shallow, non-reactive mold.Whisk the marinade ingredients in a small bowl, reserving the zest; pour over the steaks.Cover and refrigerate for 1-1 1/2 hours, turning frequently.Place the fish on a well-oiled grill or grill rack and cook over medium-high coals for 3-4 minutes, drizzling the marinade frequently.Flip and cook for another 3-4 minutes, or until the fish is well browned on the outside but still pink or slightly translucent in the center.Place on a serving platter and sprinkle with zest.