In a small bowl, use a fork to whisk together olive oil, balsamic vinegar, salt and pepper to make a vinaigrette.
Cut ciabatta loaf into sandwich-sized pieces. (I cut mine into 2-inch x 4-inch pieces.) Lightly spread the vinaigrette onto one piece of ciabatta bread.
On the other half of the bread, spread the pesto. Add turkey, cheese and tomato to the sandwich, then top with the top half of the bread.
Wrap sandwiches with folded strips of parchment and tie with baker's twine, or hold together with toothpicks. If not serving immediately, store in an airtight container and refrigerate until ready to serve.
Notes
Wrap the sandwiches in parchment paper and baker's twine or spear them with toothpicks to hold the layers together. Feel free to leave the meat off the sandwiches for a vegetarian option. Buffalo mozzarella cheese would also be excellent on this sandwich.