I’ll say it very quickly, straight away: the only way to eat tuna is raw.
It gets impossibly dry when cooked, even only seared. It’s supposed to be ‘meaty’, but that particular meatiness to me is on par with the chicken breast fillet (boring), overcooked turkey (dry) and well cooked through pork chop (boring and dry). Easy to guess I am not a fan of dry lean well-cooked meat. Okay, a lot of people like those cuts thus cooked, but I am of the ‘good to eat as long as it doesn’t run from the plate’ persuasion.
‘Tartare’, contrary to popular beliefs, originally meant a dish served with tartar sauce. I am fond of the popular belief relating the origins to the Tartar people of Central Asia who would place a raw steak under their saddle, ride off into the battle and consumed the – well, sort of minced and processed meat – hours (days?) afterwards. Yum. Well, certainly sustainably prepared.
There is the classic, beef tartare, served with a raw egg yolk (to aggravate the British fear of bacteria). The hardcore is horsemeat, bison or pork (sic) and there are also less belligerent fish varieties: salmon and tuna. Surprisingly, and that might alleviate the salmonella/toxoplasmosis worry somewhat, raw meat is actually easier to digest and may contribute to weight loss – see the Paleo diet…