In a large soup pot or stockpot, bring 4 quarts of cold water to a boil. Add 1 tablespoon of the salt and the orecchiette and cook according to package directions until al dente. Drain the pasta and set aside. Reserve 1/2 cup of the cooking liquid for the sauce.

While pasta is cooking, heat 2 tablespoons of the olive oil in a large skillet and, when hot, add the onion and remaining 1/4 teaspoon of salt and cook, stirring often, until onions are golden, about 8 minutes. Add the garlic and cook for 2 minutes. Add the prosciutto and crushed red pepper and cook, stirring, for 3 minutes. Add the broccoli rabe and black pepper and cook, tossing, until the broccoli rabe is wilted, 1 to 2 minutes. Add the lemon juice, lemon zest, and sun-dried tomatoes and stir to combine. Add the drained pasta and the reserved 1/2 cup of pasta cooking liquid and cook, stirring, until everything is heated through and well-combined. Remove from the heat and add the parsley, remaining tablespoon of olive oil, and the ricotta salata; toss thoroughly to combine.

Serve immediately.