Boil the pasta in salted boiling water until al dente. Drain. Heat the olive oil in a large pan and saute the chicken sausage until it starts to brown, about 5 minutes. Add the chili flakes and garlic and continue cooking for 1 minute. Add the spinach and cook until wilted, another minute. Add the pasta to the sausage mixture and saute for 1 minute over medium heat. Place the pasta in a bowl and top with the freshly grated Parmigianino.