Boil some water in a large pot and cook your pasta following the instructions on the packaging and proceed to make the sauce while it is cooking.
Place a wok or a large pan on medium heat and add the chorizo when the pan is hot. Fry them until crisp.
Remove the chorizo from the pan and set it aside on a plate.
Add the shrimps to the pan and cook for a minute, until they turn pink. Don't be tempted to cook longer, as they will get cooked more when finishing the sauce.
Remove the shrimps from the pan and set them aside on a plate.
Add the butter to the pan and add the chorizo, saute for another minute before adding the red onions and garlic.
Saute the onions for a minute until slightly softened and then add the peppers.
Sauté the peppers for a minute and then add the red wine.
Let the wine evaporate and then add the tomatoes, tomato paste, smoked paprika, salt, freshly ground black pepper, and chilies (if using).
Cook them until the tomatoes are slightly softened, add some pasta cooking water, and cook for a few more minutes.
Add the parmesan cheese, herbs, and pre-cooked shrimps to the sauce, give it a good stir and add the cooked pasta to the sauce.
Nicely combine the pasta with the sauce, and cook together for another minute before serving.