Bring a large pot of salted water to a boil and cook the rigatoni according to package instructions until al dente. Reserve 1 cup of pasta water before draining.

Heat the olive oil in a large skillet over medium-high heat.

Add the zucchini slices to the skillet and sauté for 5 to 7 minutes until they are tender and golden brown.

Stir in the minced garlic and red pepper flakes, and cook for 60 seconds until fragrant.

Add the cooked rigatoni to the skillet along with the lemon juice and half of the reserved pasta water.

Toss the mixture over medium heat for 2 minutes to allow the sauce to emulsify.

Remove the skillet from the heat and stir in the lemon zest, grated Parmesan cheese, and chopped parsley.

Season with salt and black pepper to taste, adding more pasta water if necessary to achieve a silky consistency, and serve immediately.