- ¾ cup olive oil
- ¼ cup white vinegar
- 1 garlic clove, minced
- 1 tablespoon Dijon mustard
- 1 teaspoon freshly ground black pepper
- ½ teaspoon salt
- ½ teaspoon ground cumin
- 2 cups cooked black beans, still warm, drained
- 2 cups cooked white beans, still warm, drained
- 2½ bell peppers, assorted colors (red, green, yellow) cored, seeded, and diced (about 2 cups)
- 1 medium red onion, diced (about 1 cup)
- 1 to 2 tablespoons jalapeno peppers to taste, seeded and finely minced (see note)
- Leaf lettuce (optional)
- To prepare the dressing, whisk together in a large bowl the oil, vinegar, garlic, mustard, black pepper, salt, and cumin.
- Add the beans, bell peppers, onion, and jalapeno peppers. Mix well. Taste and adjust seasoning. Cover and refrigerate until 30 minutes before serving. Serve on lettuce, if desired.