Cook the linguini in a large pot of well-salted boiling water until al dente. Drain.
In a large skillet over medium-high heat, heat the olive oil. Sauté the sausage for 2-3 minutes until they begin to brown. Stir in the pepper flakes and garlic and cook for another minute. Remove from the heat and toss with the pasta and arugula in a large bowl.
Season to taste with salt and pepper and garnish with Parmesan.