Heat the oil in a large pan and fry the chorizo for 2 minutes until golden. Add the onion and garlic and cook for about 5 minutes or until soft and golden.
Stir in the paprika and cook for a further minute, then add the capers, oregano, lemon rind, sugar, red pepper and tomatoes. Bring to the boil, then reduce the heat and simmer gently for 15 minutes.
Meanwhile, cook the penne in lightly salted boiling water according to the instructions on the packet.
Drain the pasta and stir it into the chorizo sauce. Serve immediately with a drizzle of chilli oil (if used) and the freshly grated Parmesan.