Kidney Bean and Crisp Vegetable Salad

Kidney beans are edible only if they are cooked first to break down a poisonous substance, phytohemagglutinin, found in them. Cooked kidney beans, which stay firm on the outside but are soft and possibly mealy on the inside, are the principal ingredient in this simple bean salad. It costs very little to prepare it, especially if one has cold, cooked beans on hand or in a can. To introduce an interesting contrast of textures they can be mixed with crisp vegetables, especially tsukemono, a ty