boil the beans (soaked the night before). Drain and do not throw away the cooking water. Blanch pork rind for five minutes in boiling water so lost a bit of fat.
Take a pan with the onions, carrot and celery in a few tablespoons of oil. Add pork rinds cut into strips and let them cook for a few minutes. Pour also beans, salt, pepper and tomato sauce. Cook over low heat, adding if necessary, the cooking water from the beans.
Serve the beans with pork rind with thick toast.