Slice the pork into strips, season and fry in a heavy bottomed saucepan until brown all over. Remove from the frypan and drain off any excess oil.
Add the chorizo to the saucepan and brown for two minutes then add the onions, four teaspoons of paprika, 2 teaspoons of chilli flakes and the garlic. Fry for a further 2 minutes until the onion has softened.
Return the pork back to the saucepan along with 250ml of water and the tomatoes. Season to taste.
Simmer the stew for 1 hour on a low heat with a lid on; add water if it looks like it needs it. After 1 hour remove the lid and add the cannellini beans. Simmer for a further 30 minutes.