Set a oven rack on the highest position in the oven. Slide in a sheet pan, pizza stone or cast iron skillet and peheat oven to 550F (287C).
To build the pizza, place each piece of Naan on a sheet of parchment paper. Dividing the ingredients between the two pizzas, spread the pesto over the flatbread, almost to the edges. Layer the asparagus, mushrooms, kalamata olives, a pinch of red pepper and oregano, mozzarella and a few pieces of feta (save some feta for the top later).
Remove the pan from the oven and carefully transfer the pizza to the pan. If using a cast iron skillet, you'll need to bake one at a time. Bake on the top rack for five minutes. Remove from oven and transfer pizza to a cutting board. Place a generous hand full of salad mix on top of the pizza, add a bit of feta, a few sliced tomatoes, and a drizzle of balsamic vinegar. Slice with a pizza wheel and serve immediately.