Pan Bagnat

Ingredients

• 1 tablespoon red wine vinegar
• 1/2 teaspoon Dijon mustard
• 1/2 teaspoon kosher salt
• 1/4 teaspoon freshly ground black pepper
• 3 tablespoons olive oil
• 1 (16- to 18-inch) baguette
• 12 ounces canned tuna packed in oil or water, drained and crumbled
• 1 small green pepper, sliced into rings
• 1 small red onion, sliced into rings
• 2 hard-boiled eggs, sliced
• 1 cup kalamata olives, chopped
• 1 tomato, thinly sliced