Make ahead: prepare the sundried tomato pesto. You can make it up to 1 week in advance. Store-bought is fine too.
Make ahead: make the rosemary focaccia bread. It's best to make it the same day, but you can make it the day before. Store-bought is fine too.
To assemble the sandwich: cut the foccacia in 6 parts (or less if you have a smaller batch of focaccia). Then slice each piece horizontally so that the top and bottom parts of each piece of bread are separated. Spread with some sundried tomato pesto, then add arugula, shaved turkey, tomato slices, mozzarella slices. Spread the top with more pesto, and top your sandwich.
Disclaimer: Nutritional values (per serving) are approximates only.