Preparation
Mix all ingredients (except tuna) in a non-reactive bowl that is just big enough to hold the steaks in one layer. Marinate the steaks 30 mins-2 hrs before serving. If marinating longer than 30 mins, keep in the fridge and remove to room temp 30 mins before cooking.
Set a large frying pan on med-high heat
Remove tuna from marinade & dry on paper towels
When the pan is hot, pour 2 TBSP of oil from the marinade onto the skillet. Sear the tuna steaks 2.5 mins on one side and 1.5 mins on the other