White onions are crisp, mildly pungent bulbs commonly used in cooking and eaten raw. They work well in salsas, salads, sautés, soups, and Mexican and Latin dishes. Sold loose by weight, use within a couple weeks stored in a cool, dry, ventilated place. Trim roots and peel before slicing or dicing. Low in calories and a source of vitamin C, onions add flavor without many calories.