High-Protein Tuna & White Bean Melt

Name: High-Protein Tuna & White Bean Melt
Cook time: 15 min
Total time: 15 min
Cuisine: American
Ingredients: 1 (5-ounce) can no-salt-added water-packed tuna, drained; ½ cup rinsed canned no-salt-added white beans; ¼ cup minced celery; ¼ cup minced pickled red onion; 3 tablespoons reduced-fat mayonnaise; 2 tablespoons sweet pickle relish; 1 tablespoon minced fresh dill; 1 tablespoon minced fresh chives; 2 teaspoons minced rinsed non-pareil capers; ½ teaspoon freshly ground black pepper; 2 tablespoons unsalted butter, at room temperature; 4 (1-ounce) slices whole-wheat bread; 2 (1-ounce) slices Cheddar cheese