Put the drained beans, onion, pepper and garlic into a food processor. Push the mixer button a few times until everything has been chopped, but is still coarse. Put the mixture into a bowl, stir in the sauce, breadcrumbs and seasoning. Stir the cornflour into the water, stir into the mixture.
With wet hands, shape the mixture into 6 burgers. Fry in hot oil for approx. 1 1/2 mins. on each side until golden-brown.