Three-bean salad marinated in a sweet-tart vinaigrette is a dish that appears in virtually every American church cookbook published between 1950 and 1990. Its ubiquity is a testament to how well it travels ÃÂÃÂÃÂÃÂÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂàit improves overnight, feeds a crowd, and requires nothing but a bowl and a can opener. Mary April's version, tossed with fresh onion and green pepper, is the real article.