Cut pepper into 1/2 inch pieces; chop onion.  In a medium-sized bowl, mix the peppers and onions with the beans and 1/4 cup chopped cilantro; set aside.

Using a food processor (or high powered blender), blend together 1/2 cup of cilantro, almonds, lime juice, water, garlic, cumin and salt.  Being sure to scrape the sides of food processor, blend until smooth.  Add the yogurt, pulse a few times until mixed. 

Mix the dressing in with the bean mixture. Divide lettuce among 4 plates and top each bed of lettuce with bean mixture.  Serve grapes on the side.