Lemony Tuna and White Bean Antipasto Salad

Name: Lemony Tuna and White Bean Antipasto Salad
Ingredients: 1/4 cup plus 2 tablespoons fresh lemon juice; 1/4 cup plus 2 tablespoons fruity extra-virgin olive oil, plus more for drizzling; Two 6-ounce cans olive oil—packed tuna, drained and broken into large chunks; One 19-ounce can cannellini beans, drained and rinsed (about 1 1/2 cups); 24 pitted Calamata olives, coarsely chopped; 2 cups thickly sliced celery hearts and leaves; 2 tablespoons capers, drained, or if packed in salt, rinsed; 2 heaping tablespoons finely chopped flat-leaf parsley; 2 teaspoons finely grated lemon zest; 1 teaspoon minced garlic; Freshly ground pepper; 2 roasted red peppers from a jar or 4 piquillo peppers from a jar; Kosher salt; 4 lemon slices, for garnish