Spray a 13 x 9-inch baking dish with cooking spray or lightly brush with olive oil. Set aside.
Cut the stem and blossom ends off the zucchini and slice lengthwise into 1/8-inch or 3 mm slices. Aim for 30 good slices.
Give the zucchini a generous pinch of salt on both sides, then place it on 2-3 layers of paper towels and let it stand for 1 hour.
Meanwhile, combine the ricotta, half the mozzarella cheese, half the Parmesan cheese, pesto, a pinch of salt, and freshly ground black pepper to taste in a small bowl. After adjusting the seasoning, stir in the egg. Set aside.
Combine the marinara sauce, tomatoes, garlic, and crushed red pepper flakes in a medium bowl. Set aside.
Preheat oven to 375 degrees. Spread the marinara sauce into the prepared baking dish, reserving 1 cup to place on top of the zucchini ravioli.
Pat the zucchini dry with paper towels.
Arrange three zucchini strips in a star pattern with the nicest zucchini strip placed first (on the bottom). Repeat nine more times. Place even amounts of the ricotta, cheese, and pesto filling in the center of each "star." (Approximately 3-4 tablespoons each.) Fold the zucchini strips up and over the filling to form a neat parcel, making sure the bottom strip wraps snugly. Place in the prepared baking dish.
Top each ravioli with equal amounts of the remaining marinara, followed by the remaining Mozzarella and remaining Parmesan cheese.
Cover lightly with aluminum foil. Bake for 30 minutes. Remove the foil and bake for another 15-20 minutes or until all the ravioli in the center of the baking dish register 165 degrees on an instant-read thermometer.
Sprinkle with chopped fresh parsley and serve.