Ingredients

• 2 6-oz. cans tuna packed in oil 
• 3 cups drained and rinsed canned white beans, preferably cannellini (from 2 15-oz. cans) 
• 1 small-medium red onion, sliced thin 
• 1 Tbsp drained capers 
• 2 bunches watercress (about ¾ pound), tough stems removed and leaves chopped (about 2 cups) or a mix of greens and fresh herbs, such as arugula, basil, chives, mint, parsley, cilantro, dill, stems removed and leaves finely chopped 
• 2 Tbsp olive oil 
• 1 Tbsp red or white wine vinegar 
• ¾ tsp salt 
• 1 tsp freshly ground black pepper