Pan Bagnat

Ingredients

• tablespoon red wine vinegar
• teaspoon Dijon mustard
• teaspoon kosher salt
• teaspoon freshly ground black pepper
• tablespoons olive oil
• baguette
• ounces canned tuna packed in oil or water, drained and crumbled
• small green pepper, sliced into rings
• small red onion, sliced into rings
• hard-boiled eggs, sliced
• kalamata olives, chopped
• tomato, thinly sliced