Bring water to a boil in a large pot to cook spaghetti or pasta. Salt water and cook pasta according to package directions. Drain and set aside.

Heat olive oil in a large skillet or 3.5-quart braising pan. Cooking on medium, add in 2 minced garlic cloves and ¼ teaspoon red pepper flakes. Stir with a wooden spoon to keep moving, cooking for about 1 minute.

Carefully pour in 28-ounces canned whole, peeled tomatoes. Use the wooden spoon or a fork to break apart the whole tomatoes. Reduce heat to low, if needed, to keep tomatoes from splattering.

Once tomatoes are broken up, season with ½ teaspoon kosher salt and ¼ teaspoon black pepper. Bring to a simmer and cook for about 5 to 7 minutes.

Add 10 ounces canned tuna (2 cans) and add into the tomato sauce with liquid. Break up the tuna into chunks and stir the liquid into the sauce. Return to a simmer and cook for about 3 minutes.

Stir in the cooked pasta and toss to combine. Once pasta is just heated, sprinkle on flat-leaf parsley and serve.