Never tried this before and wasn't sure how it would turn out actually I had my doubts. It is fantastic
6 in thick tuna steaks (YFT is okay) 2 cups pulp free OJ, 1/2 cup soy sauce, 1 cup red wine vinegar, 1/2 cup olive oil, some chopped onion, 4 gloves garlic, 1tsp red pepper flakes, 1TBSP cumin, 1tsp freshly ground black pepper, 1.5tsp pickling spices( I skipped this, because I was out of it), 1 6 oz. can tomato paste, 1/2 cup sugar. Mix all, put tuna in dish large enough to hold them in one layer. cover with marinade. put in frig overnight, up to 24 hrs. turn a few time during marinating time. Grill on oiled grill 3 mins. per side. pre-heat oven to 375, put tuna in baking dish, put 1 TBSP marinade or more over steaks, bake in oven for 4 or 5 mins. If you like you can put a little butter on top when serving. I used thicker steaks maybe 1.5 -2 ". Wife just loved it.