Preheat Outside Grill on Medium High setting when you start your prep. Or start your charcoal grill about 30 minutes before you plan to grill tuna.
Pat tuna steaks with paper towels to remove excess moisture then place in a shallow dish.
Mix all spices with oil and lemon juice in a small bowl with a fork or wisk. Allow to rest for at least 5 minutes to blend together.
Brush mixture on both sides of Tuna steaks and allow steaks to rest for another 5 minutes.
Grill steaks on hot grill 2-5 minutes on each side to attain desired doneness. For well done there should still be some pinkness to the center. Most prefer barely warm red centers. Try not to overcook.