Ultimate Smoked Tuna Melt - Traeger Grills

Ingredients

• 1 1/4 Pound fresh tuna
• 1 Teaspoon Aleppo pepper
• Kosher salt and freshly ground black pepper
• 1 Stalk celery, finely chopped
• 1/4 Cup chopped red onion
• 3 Tablespoons finely chopped fresh flat-leaf parsley
• 3 Tablespoons chopped fresh chives
• 2 Tablespoons fresh chopped fresh dill
• 1 Tablespoon jalapeño, finely chopped
• 1 1/2 Teaspoon finely grated lemon zest
• 2 Tablespoons fresh lemon juice
• 1/2 Cup coarsely chopped cornichons plus ½ teaspoon brine
• 2 Tablespoons chopped capers plus ½ teaspoon brine
• 1/2 Teaspoon red pepper flakes
• 1/2 Cup mayonnaise, plus more to taste
• 8 Slices sandwich bread
• 4 Ounces unsalted butter
• 8 deli slices cheddar cheese