1. Heat the oil in a large, lidded nonstick frying pan or flameproof casserole dish over a medium-high heat. Add the sausages and cook for 5 mins, turning frequently, until browned all over. Remove from the pan and set aside on a plate.
2. Add the onion, celery, carrot and garlic to the pan. Cook over a medium-high heat for 10 mins until softened and lightly golden. Return the sausages to the pan along with the tinned tomatoes, stock and smoked paprika. Season lightly and stir. Bring to the boil, then reduce to a simmer for 20 mins until the sauce has thickened slightly.
3. Stir in the beans and greens, then cover and simmer for a further 5 mins until the greens have softened. Spoon into bowls and grind over some black pepper to serve.