Put a medium pan on the heat and tip in the tomatoes, followed by a can of water. While the tomatoes are heating, quickly chop the chorizo into chunky pieces (removing any skin) and shred the cabbage.
Pile the chorizo and cabbage into the pan with the chilli flakes and chickpeas, then crumble in the stock cube. Stir well, cover and leave to bubble over a high heat for 6 mins or until the cabbage is just tender. Ladle into bowls and eat with crusty or garlic bread.