1/2 cup mayonnaise
1/2 cup finely diced sweet pickles (about 2 pickles)
4 (4 to 6-ounce) albacore tuna steaks
Kosher salt and freshly ground black pepper
Olive oil, for drizzling, plus 1/4 cup
4 teaspoons herbs de Provence
4 slices sharp white Cheddar
1 (1-pound) loaf ciabatta bread, halved horizontally (see Cook's Note)
2 cups arugula, thinly sliced
For the mayonnaise: In a small bowl, mix together the mayonnaise and sweet pickles until smooth.
For the sandwiches: Place a grill pan over medium-high heat or preheat a gas or charcoal grill. Season the tuna with salt and pepper. Drizzle with the oil and sprinkle with the herbs de Provence. Grill for 3 to 4 minutes on each side for medium-rare. Place a slice of cheese on each piece of fish during the last minute of grilling. Using a pastry brush, brush the bottom half of the bread with 1/4 cup of olive oil. Cut into 4 pieces, each about 4-inches long and 3-inches wide. Grill, cut side down, for 30 seconds to 1 minute until toasted and golden.
Spread the grilled bread with the sweet pickle mayonnaise. Place a tuna steak on top. Top with the arugula and drizzle with olive oil. Season with salt and pepper, to taste, and serve.
Cook's Note: Make the leftover top half of the ciabatta into croutons by cutting into 1-inch pieces, drizzling with olive oil and baking for 10 to 12 minutes in a preheated 375 degree F oven. Alternatively, tear the bread into small pieces, allow to dry, and blend in a food processor to make bread crumbs