Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente, usually around 8 to 10 minutes. Reserve about 1/2 cup of pasta water before draining.
While the pasta cooks, heat 2 tablespoons of olive oil in a large skillet over medium heat. Add the minced garlic and red pepper flakes, sautéing for about 30 seconds until fragrant but not browned.
Pour in the can of diced tomatoes along with their juices. Stir in the drained chickpeas, black olives, and capers. Let the mixture simmer for 5 minutes, allowing the flavors to meld and the sauce to thicken slightly.
Gently fold in the drained tuna, breaking it into chunks but keeping some texture. If the sauce feels too thick, add a splash of the reserved pasta water to loosen it up. Season with salt and pepper to taste.
Add the cooked spaghetti directly into the skillet with the sauce. Toss everything together over low heat for 1 to 2 minutes, ensuring the noodles are evenly coated.
Remove from heat and sprinkle with fresh chopped parsley for a burst of color and freshness. Serve immediately and enjoy the robust flavors of this quick, satisfying meal.
