Black Bean, Green Pepper, And Red Onion Dip

In a large saucepan let the beans soak in cold water to cover for 1 hour, drain them, and in the pan combine them with 2 quarts of the water. Bring the water to a boil and cook the beans at a slow boil for 1 hour, or until they are tender. While the beans are cooking, in a large heavy skillet cook the bell pepper and the onion in the oil over moderate heat, stirring, until the vegetables are softened. Drain the beans, reserving 1/2 cup of them, add the remaining beans to the bell pepper mixture with the remaining 1/4 cup water, and simmer the mixture, covered tightly, for 15 minutes, or until the beans are very tender. In a food processor blend the mixture with the vinegar and salt to taste, pulsing the motor until the mixture is combined well but not pureed smooth. Transfer the dip to a bowl and stir in the reserved 1/2 cup beans. The dip may be made 2 days in advance and kept covered and chilled. Garnish the dip with the reserved bell pepper and onion and serve it with the tortilla chips. Makes about 3 cups. Gourmet October 1993