Grilled Tuna Melt Sandwich with Cornichon Caper Aioli

Ingredients

• 2 ahi tuna filets
• 2 tsp olive oil
• 1 tsp kosher salt
• 1 tsp coarse ground black pepper
• 1 baguette
• 4 slices Swiss cheese
• 1/4 cup arugula leaves
• 2 tbsp celery leaves
• 1 cup mayonnaise
• 4 cornichons (chopped)
• 2 tbsp red onion (chopped)
• 2 tsp capers (chopped)
• 1 tbsp Dijon mustard
• salt
• pepper