Step 1

In a mixing bowl, combine the sour cream, mayonnaise, and a squeeze of lime or lemon juice. Whisk until you have a smooth, creamy sauce. Set the sauce aside or store in the refrigerator if you're making it more than 15 min ahead of time.

Step 2

In another bowl, stir together your chopped onions and finely chopped cilantro until evenly mixed. If you don't have white or yellow onions, you can use an equivalent amount of scallions.

Step 3

Heat a teaspoon of vegetable oil in a cast iron skillet. Once it's hot, sauté the tuna fish. You're aiming to slightly brown it, not blacken it.

Step 4

If you're adding vegetables as suggested in the upgrades below, add them to the skillet before the tuna.

Step 5

Prepare your tortillas by warming them in an oven at 175°F or toast them briefly on both sides in a clean pan or skillet – no oil required.

Step 6

To assemble your tacos, lay them flat on a clean work surface or individual plates. Add a quarter of the tuna fish filling onto each one. On top of that, add a portion of the onion and cilantro mixture. Finally, top with your sour cream and mayonnaise dressing. Use a taco holder for them to stay put.

Step 7

Serve with a side salad, salt and pepper, and a bottle of your favorite hot sauce.