Cut ciabatta in half horizontally. Spread bottom half with tapenade. Drizzle cut side of top half with vinegar and oil.
Arrange salami on top of tapenade, followed by the prosciutto, cold cuts, mozzarella, red pepper, and basil. Sprinkle with pepper to taste and place top half of loaf on filling.
Wrap sandwich thoroughly with plastic wrap or foil. Place a heavy cutting board or other flat object on top of sandwich and weight it down with a 2- to 4-lb. weight (such as a large pot or six-pack of soda). Let sit 30 minutes to 2 hours. Unwrap, cut into eighths, and serve.