Cut the ciabatta in half horizontally. Spread the mustard on the cut side of the top half and the cranberry sauce on the bottom half. On the bottom half, stack the ham, turkey, cheese, pickles, and top half of the bread. Press down firmly and cut crosswise into 4 even sandwiches.
Heat a grill pan to medium. Working in batches if necessary, place the sandwiches on the pan and place another very heavy skillet on top. Grill, turning once, until the bread toasts and grill marks appear, about 8 minutes. Serve hot or warm.