Bring a large pot of salted water to a boil and cook the orecchiette according to package directions until al dente.
During the last 2 minutes of pasta cooking, add the chopped broccoli rabe to the boiling water to blanch it until vibrant green and slightly tender.
Drain the pasta and broccoli rabe, reserving about 1/4 cup of the starchy pasta water.
In a large skillet over medium heat, add the olive oil and sliced chicken sausage, browning the sausage for 3-4 minutes until golden.
Add the minced garlic and red pepper flakes to the skillet, sautéing for 1 minute until the garlic is fragrant but not browned.
Add the drained pasta, broccoli rabe, and reserved pasta water to the skillet, tossing everything together to coat.
Season with sea salt, black pepper, and fresh lemon juice, then remove from heat.
Serve immediately topped with a sprinkle of grated parmesan cheese.