15- to 19-ounce can beans, such as chickpeas, black-eyed peas or kidney beans, rinsed • 5- to 6-ounce cans water-packed chunk light tuna, drained and flaked (see Note) • red bell pepper, finely diced • finely chopped red onion • chopped fresh parsley, divided • capers, rinsed • finely chopped fresh rosemary • lemon juice, divided • extra-virgin olive oil, divided • Freshly ground pepper, to taste • salt • mixed salad greens