Preheat the oven to 400°F and line a baking sheet with parchment paper.
Place the flatbreads on the baking sheet. Spread BBQ sauce evenly over each flatbread.
Top with shredded chicken, mozzarella cheese, and red onion slices.
Bake for 8 to 10 minutes until the cheese melts and the edges turn golden.
While the pizzas bake, place the chopped romaine in a large bowl. Add Caesar dressing and toss to coat.
Sprinkle Parmesan cheese and croutons over the salad just before serving.
Remove the pizzas from the oven, slice each one, and serve with the salad on the side.