Preparation Toast cumin in skillet over medium heat until fragrant, about 2 minutes. Whisk vinegar and oil in bowl to combine. Combine kidney beans, onion, 1 1/2 cups walnuts, and 1/2 cup chopped cilantro in large bowl. Add vinegar and oil mixture. Crumble cumin seeds between fingers and add to bean mixture. Toss gently to blend; season with salt and pepper. Let salad stand at room temperature for 2 hours. (Can be made 6 hours ahead; refrigerate. Bring to room temperature before serving.) Line and fill large bowl with lettuce leaves. Spoon salad into bowl. Garnish salad with additional cilantro and walnuts and serve.
Preparation Toast cumin in skillet over medium heat until fragrant, about 2 minutes. Whisk vinegar and oil in bowl to combine. Combine kidney beans, onion, 1 1/2 cups walnuts, and 1/2 cup chopped cilantro in large bowl. Add vinegar and oil mixture. Crumble cumin seeds between fingers and add to bean mixture. Toss gently to blend; season with salt and pepper. Let salad stand at room temperature for 2 hours. (Can be made 6 hours ahead; refrigerate. Bring to room temperature before serving.) Line and fill large bowl with lettuce leaves. Spoon salad into bowl. Garnish salad with additional cilantro and walnuts and serve.