Spread the cut sides of each half of bread with equal amounts of the olive salad and oil, about 1 1/2 cups per side. Arrange the mozzarella over the olive salad on the bottom piece of bread and top with the salami, cappocolo, mortadella, and pepperoni. Arrange the provolone on the top piece of bread, completely covering the olive salad, and place on top of the bottom half to make a sandwich.
Tightly wrap the sandwich in aluminum foil and bake until sandwich is heated through and cheeses have melted, 15 to 20 minutes.
To serve, unwrap the sandwich and slice into portions.
Kicked Up Olive Salad:
Combine all ingredients in a large nonreactive bowl and mix well. Place in a nonreactive jar (preferably glass) and store tightly covered in the refrigerator. Salad should be made at least 24 hours before using and only improves with age, can keep for up to 2 months in the refrigerator.