While there are many different ways to dress a bean salad, one of the best options is a simple vinaigrette made with olive oil, vinegar, and spices or a vinaigrette made with olive oil, lemon juice, and mustard.  This dressing will not only add flavor to the salad but will also help to keep the beans nice and crispy.  The dressing pairs especially well with cannellini beans but can also be used with other types of beans, such as chickpeas or black beans. Another great option for dressing a bean salad is a creamy yogurt-based dressing. This dressing can be enhanced with herbs and spices, which will help hold the salad together while adding a bit of creaminess.  The dressing should be light and bright, with a bit of acidity to offset the richness of the beans. And best, the salad should be finished with a sprinkling of fresh herbs for a touch of flavor.