Cover the beans with water and let soak overnight. The next day, drain and rinse. OR a quicker method is to boil the beans for 1 or 2 minutes, then let them sit for 1 hour. Then drain and rinse.
In a large saucepan, combine the beans, onion, ginger, 1/2 teaspoon of the salt and enough water to cover it all. Bring the mixture to a boil. Reduce the heat and simmer, uncovered, until the beans are tender, About 35 to 40 minutes. Drain well.
In a food processor, puree the beans with the oil, vinegar, hot pepper sauce and remaining salt and pepper. Chill before serving.