Fill the tomato tin with water and pour into the slow cooker pot. Half fill the can again and add this too (this should make 600ml/20fl oz water in total). Add the chorizo, beans, paprika ...
Soak the beans overnight in plenty of fresh cold water. The next day, preheat the slow cooker to low. Heat the olive oil in a frying pan over low–medium heat, add the onion and cook for about 5 ...