Combine marinade ingredients in a blender and whirl until thoroughly mixed. Pour over the tuna and marinate for at least 1 hour, preferably longer.
Put tuna steaks in a well oiled, hinged fish grill or brush a barbecue grill with oil after the coals are hot. Grill tuna for 6-8 minutes per side, basting several times with the marinade.
Tuna may also be prepared in the broiler. Broil for 6-8 minutes per side, basting frequently.
Wine: California Chardonnay or Kirin Beer