Tuna Melts - Valerie Bertinelli

Ingredients

• 4 (2.6-ounce) pouches solid white albacore tuna in water
• 4 celery stalks with leaves, chopped (about 1 cup)
• 1 hard-cooked egg, chopped
• 1⁄2 cup mayonnaise
• 1⁄4 cup drained capers or chopped pimiento-stuffed Spanish olives
• 2 tablespoons chopped fresh flat-leaf parsley
• 1⁄2 teaspoon lemon zest, plus 1 tablespoon fresh lemon juice
• 1⁄2 teaspoon kosher salt
• 1⁄4 teaspoon black pepper
• 8 hearty white deli bread slices
• 8 Havarti cheese slices
• 1 ripe avocado, quartered and sliced
• 1 large tomato, sliced
• 1 cup loosely packed arugula
• Olive oil