If you are using dried beans, boil them in water thrice their volume and set aside to cool. If you are using canned ones, rinse well. Combine the beans, pepper and corns in a large salad bowl.
Prepare the dressing for the salad in a smaller bowl. Combine the olive oil, vinegar, lemon juice, sugar, salt, garlic, cilantro, cumin, black pepper and chili powder. Stir together the ingredients well to get an even mixture.
Pour this dressing over the bean mixture and mix well so that the ingredients blend together in taste. Refrigerate now for at least an hour before serving. The salad tastes best when cold.