Bring a large pot of salted water to a boil, then salt generously. Drop in the rapini and cook until the rapini turns bright green and partially cooks, 2 to 3 minutes. Use a spider to transfer the rapini to a bowl of ice water to rapidly cool, reserving the boiling water. Drain the rapini, then cut into 2-inch pieces and set aside.
Place a large skillet or heavy-bottomed pan over medium-high heat and add a drizzle of olive oil. Add both sausages and cook, breaking up into smaller pieces, until golden brown and crispy, 5 to 8 minutes. Add the garlic and crushed red pepper flakes if using and cook for an additional minute.
Meanwhile, add the Ricotta Cavatelli to the boiling water and cook until the cavatelli are al dente and begin to float to the top, 3 to 5 minutes.
Add the cooked pasta and rapini to the skillet, along with 1/2 cup reserved pasta water. Season with cracked black pepper. Toss to coat the pasta, then remove the skillet from the heat. Stir in the pecorino and serve immediately, with more cheese grated over the top and a drizzle of olive oil.
Combine the ricotta, eggs and salt in a large bowl, then stir into the flour. Gently combine with your hands to bring together into a dough. Knead the dough together, adding additional flour until the dough is firm and not sticky. Tightly wrap in plastic and rest in the refrigerator for at least 1 hour and up to overnight. Cut the dough into quarters. Working with one quarter at a time, roll the dough on a lightly-floured surface into a 1/4-inch-thick rope. With a knife, cut the rope into 1/2-inch pieces. Use a bench scraper or your index and third fingers held together to gently press down on each piece, beginning at the top and moving down toward the bottom, dragging the bench scraper toward you and causing the pasta to roll over on itself. Transfer the formed pasta to a lightly-floured baking sheet and let dry at room temperature for at least 30 minutes. (At this point, the pasta can be frozen in a single layer and stored in a resealable plastic bag in the freezer.)