Bring a pot of salted water to a boil. Add the chickpea pasta and cook according to the package instructions. Reserve the amount of pasta water listed in the ingredients, then drain the pasta and set aside.

Heat oil in a skillet over medium heat. Add the onion and a pinch of salt. Cook until softened and beginning to brown, 7 to 10 minutes.

Add the garlic and crushed red pepper flakes. Feel free to adjust the amount of red pepper flakes according to your spice preference. Cook for 1 minute, until fragrant.

Add the pasta sauce and cook, stirring occasionally, for 4 to 6 minutes, until lightly simmering. Stir in the tuna and season to taste with salt and pepper.

Stir in a small amount of the reserved pasta water as needed to loosen the sauce. Discard any remaining pasta water.

Serve the sauce over the cooked pasta.