Prepare the ingredients and lay it all out. Preheat a broiler on high.
In a large bowl, whisk together 1 tbsp lemon juice and 2 tbsp oil. Season to taste with salt and pepper. Set aside.
1 large lemon, 2 tbsp olive oil
Brush both sides of the naan with oil. Place on a sheet pan under the broiler for about 3 minutes until the top is developing good color. Remove from the oven.
2 pieces naan, 1 tbsp olive oil
Flip the naan so the bottom is the crispy side. Divide the sliced mozzarella among the naan, then top with tomato slices to cover (some can be for the salad). Season with with some of the salt and fresh pepper. Sprinkle with half of the Parmesan.
4 oz fresh mozzarella, 8 oz tomatoes, 1 tsp salt
Return flatbreads to the oven and broil until the cheese looks softer or melted, about 3 minutes. Reduce heat if everything is browning too quickly. Transfer to a cutting board to cool briefly.
Finish the salad. To the large bowl with the oil and lemon juice, mix in remaining tomatoes, arugula, walnuts and parmesan.
3 oz arugula
Sprinkle some of the lemon zest and the 2 oz pesto over the top of the flatbreads, then cut into wedges.
2 oz basil pesto