For the sandwich:

• 1/4 tablespoon olive oil
• 1/2 cup thinly sliced red onion
• 8 (6-ounce) cans or jars Italian light tuna in oil
• 1/2 cup chopped parsley
• 2 tablespoons capers
• 2 tablespoons Kalamata olives, quartered lengthwise
• 3 cornichon pickles, chopped
• 1 1/2 teaspoons lemon juice
• 2 Roma tomatoes, grilled, peeled and cut into eighths
• Salt
• Pepper
• 3 (19-ounce) loaves ciabatta bread
• 12 ounces arugula
• 1 cup shaved fennel, about half a fennel bulb
• 1 cup lemon vinaigrette

Make lemon vinaigrette: Pour 1 cup canola oil into a medium bowl. Whisk in the lemon juice, vinegar, shallots, salt, pepper and sugar. Set aside. (Makes 1 1/4 cups.)

Heat the olive oil in a small saute pan over medium heat. Add the sliced onion and cook 4 to 5 minutes until softened.

Drain the tuna, reserving a few tablespoons of oil with which to moisten the salad. Flake the tuna and combine it with the parsley, capers, olives, cornichons, lemon juice, tomatoes, onions and reserved oil. Season with salt and pepper to taste.

Cut an inch off the end of each loaf of bread. Cut the bread into 4-inch pieces and slice in half. Remove some of the soft center so the sandwich isn't doughy. Grill the bread lightly.

In a large bowl, toss the arugula and fennel with the lemon vinaigrette.

For each sandwich, place some of the arugula salad on the bottom piece of grilled bread. Top with about 1 1/4 cups tuna mixture. Place more arugula on the tuna and finish with the top piece of bread. Slice in half diagonally and serve.

Serves 8.