Mix everything in a bowl, cover and refrigerate until ready to make sandwiches.
Pre-heat the oven to 400 degrees F. Slice the ciabattas in half and layer 1/4 of the roast pork into each, followed by 1/4 of the ham, then cheese (if using) and finished with the olive salad. Put the top on each ciabatta and wrap each one individually in foil. Place the sandwiches on a baking tray, place a slight smaller baking tray then place foil-wrapped brick on top of sandwiches (you will need 2 bricks). Bake for about 20 minutes until the sandwiches are crunchy on the outside, gooey in the middle. Unwrap immediately and serve.
Cooking Under a Brick
Cooking anything under a brick sounds odd at first, but it's really a useful tool for sandwiches, boneless chicken pieces, burgers, steaks, even shrimp-anything that is dense enough not to fall apart beneath the weight of the brick (which typically weighs about 4 1/2 pounds). What the brick does for chicken breast is compress the chicken so that it cooks uniformly, making all surface area golden and crispy. A foil wrapped brick is great to use on sandwiches in place of a Panini press because it does the same thing as the expensive appliance. Using a brick as a Panini press works great in a small toaster oven, too.