In a large pot, cook the rigatoni pasta according to the package directions for al dente pasta. Reserve a cup of pasta water when draining.
While pasta is cooking, start on the sauce. In a large skillet heat olive oil over medium heat. Add onions and cook for a couple of minutes. Then add garlic and calabrian chilis and cook for an additional couple of minutes.
Next add the tomato paste and stir and cook for 5 minutes caramelizing a bit.
Reduce the heat medium-low heat and add the vodka. Stir and cook until for a couple of minutes until mostly absorbed.
Pour in heavy cream and combine well to create a silky smooth sauce. Add parmesan cheese and season with salt and black pepper to taste.
Reduce heat to low and add cooked pasta to the spicy vodka sauce. Also add a half cup of pasta water and stir well to full coat the pasta. If you need to add more pasta water, add it a tablespoon at a time until you reach your desired sauce consistency.
Serve hot and garnish with additional parmesan cheese. If you have it on hand, add some torn fresh basil or fresh parsley as well.