Heat the oil in a large skillet over medium heat. Add onion and green pepper
and sauté until the vegetables are well cooked, about 5 minutes. Add the tofu and
sauté for another 15 minutes, until the tofu is completely cooked.
Add ketchup, chili sauce, salt and pepper and continue to cook over low heat until
the mixture is heated through. Add a little water if the mixture is too dry.