Cook chopped chorizo in olive oil over medium heat for 2 minutes until slightly browned and the oil is coloured orange. Add chopped onions and cook for 5 minutes over low heat, then add chicken and a pinch of salt. (Do not oversalt as chorizo is salty and so is chicken stock) Cook for 5 minutes until chicken is mostly done, add minced garlic and parsley and cook while stirring for 30 seconds.
Then add rice and stir until the rice is evenly coated in oil for a minute or so, add chicken stock, saffron and lemon juice, stir to combine and bring to a boil, lower the heat, cover with a lid and cook for 15 minutes. Check for doneness. You might want to cook a few minutes longer is rice is not done or uncover if there is still too much liquid.
Add peas and stir lightly, then top with shrimp, cover and cook for 5 minutes longer. By the end, the liquid should be entirely absorbed by the rice and rice is tender but not mushy.
Taste and add more salt if needed.
Serve with lemon wedges.