Preheat the broiler. Slicing horizontally through the middle of the bread, cut out a 1/2-inch-thick layer and discard, reserving the top and bottom layers. Brush the cut sides with 1 tablespoon olive oil; broil until golden.
In a large bowl, combine the beef and pork. Mix in the remaining 1 tablespoon olive oil and the salt. Place on a plate and shape into a ball; flatten into a 9-inch patty.
Preheat a large skillet over medium heat. Transfer the burger to the skillet and cook until browned on the bottom, about 4 minutes. Using a large spatula, flip the burger and cook 3 to 4 minutes more.
Spread the dressing on the toasted bread bottom and top. Slide the burger onto the bread bottom; top with the lettuce leaves and the bread top. Cut into wedges to serve.