Free: Contests & Raffles.
Do you have to be careful to not over cook tuna? I take it you are bbq them after marinating them?
Hot cast iron, 1-2 min per side
Or pan fried with a bit of olive oil and a speck of garlic and basil.....
I recommend leaving it mostly raw and just searing the outsides. Alton brown did a show where he used a chimney charcoal starter to concentrate the heat and do this.