Ciabatta buns, sliced and laid out on a cookie sheet.
On the bottom half of the bun, layer mayonnaise, 3 slices of tomato, 3 slices good quality turkey, and one slice provolone cheese.
On the top half of the bun, layer mayonnaise, 1 tsp. pesto, 2 rings sliced red onion, and one slice provolone cheese.
So you end up with the provolone on top of both halves of the ciabatta. 
Broil for about one minute on top rack of oven, or until the cheese is bubbly.  Watch carefully, so they don’t burn. 
Put the two halves together and serve immediately, or wrap in foil and keep warm until serving.