Canned tuna packed in oil is usually high in omega 6 fats; most of us consume way too many omega-6 fats and not enough omega-3 fats, so choose tuna packed in water. (For more information on omega-6 fats, please refer to "The Skinny on Fat" post dated March 23, 2010.)
Pole-caught: Look for canned specialty tuna, which is tuna that's pole-caught. The pole-caught method results in the least amount of unintended catch of other species such as dolphin, plus it's more ecologically sustainable. Albacore, Yellowfin and Skipjack tuna are the best choices, as they are abundant in number and reproduce quickly. Specialty canned tuna can be found online and in natural food stores.
Tuna for lunch: open the can, drain it, and pour the tuna in a medium sized bowl, saving the liquid for your cat. Separate the meat with a fork. Add chopped organic celery (yes, there is a difference in taste), onion, and fresh dill. Drizzle a little olive oil on top if you need it for satisfactory mouth-feel, and party-dress it with the juice of a lime. Hit it with a squirt of your favorite hot sauce if that's your thing. Serve with 2 cups or more of your favorite home-grown or organically grown baby lettuce laced with a tablespoon of extra virgin olive oil, fresh lime juice, and coarse sea salt and freshly ground pepper to taste.
Mayo? We don't need no stinkin' mayo!