Preheat oven to 400° F. Bring a large pot of water to a boil. Place the zucchini in a baking dish in a single layer.
Drizzle with the oil. Top with crushed red pepper, garlic, 3 tablespoons of the Parmesan, pepper, and ½ teaspoon salt.
Roast zucchini for 20 minutes, tossing halfway through, until tender and just golden brown.
Meanwhile, add the ravioli and remaining salt to boiling water. Return to a boil, stirring frequently to prevent ravioli from sticking.
Cook ravioli for 3 minutes after they begin to float. Drain and place in a large bowl.
Toss the ravioli gently with roasted zucchini, half the parsley, and half the remaining Parmesan. Serve immediately with remaining parsley and Parmesan.