Mist a large lidded pan with cooking spray and fry the onion and chorizo 5 minutes over a medium heat. Add the pepper and cook 5 minutes.
Stir in the garlic, paprika, saffron and rice and cook 1 minute. Pour in the stock, bring to the boil, then reduce the heat and simmer, covered, 15 minutes.
Stir in the prawns, peas and half the parsley, cover and cook 5 minutes.
Remove the lid and cook 3-4 minutes until the stock is absorbed. Season, scatter over the remaining parsley and serve with lemon wedges.