Fresh or canned cranberry beans (borlotti in Italian) are the ideal bean to use here. Look for a premium canned tuna packed in olive oil, ideally ventresca (pages 14–15), not the flavorless tuna packed in water. This salad is substantial enough to be a light lunch.
You can assemble the salad up to 1 day ahead and keep it in the refrigerator. Wait to add the onion and to season it until just before serving.
© 2005 Giuliano Hazan. All rights reserved.