i had dinner at a friend's house recently and he grilled tuna steaks that were out of this world.
he told me he marinated the tuna in a mixture of (making this up based on memory) maybe sesame oil, rice wine vinegar, soy sauce, garlic, ginger, etc.
then he sliced the tuna steak down the middle on the horizontal and soaked some arugula in the marinade then stuffed the incision with the arugula then seared them on the grill. incredible.
well, he is out of the country, i've got some great tuna steaks and i'd like to try and come close to this recipe. i figure the hounds out there have some great marinade ideas along these lines...
probably even better than the original!