Bring a large stock pot of water to a boil over medium heat, then add in the salt and the cauliflower. Cook for 3 to 4 minutes. Heat 2 tablespoons of olive oil in a large saute pan, and saute the garlic and red pepper flakes for 1 minute. Remove the cauliflower from water with a large strainer or spider and add it to the pan with the garlic-red pepper mixture. Saute briefly until starting to brown, about 3 to 4 minutes. Deglaze the pan with the chicken stock, add in the spinach, cover and let wilt for 2 minutes. Stir in the tomatoes and capers with juice and reduce the heat. Remove the cover and let simmer for 5 minutes.
Return the cauliflower water to boil, adding more water, if necessary, to cook the pasta. Add the pasta add cook to al dente. Remove the pasta from the water and add it to the pan with the sauce, adding a little pasta water, if needed. Stir gently to combine, transfer to a serving bowl and sprinkle with half of the cheese. Garnish with the parsley and drizzle the remaining 2 tablespoons of olive oil. Serve immediately with remaining cheese on the side.