Put the ricotta in a strainer set over a bowl and strain in the fridge overnight.
Preheat the oven to 425 degrees F. Preheat a grill or grill pan to medium-high heat.
Season the zucchini, squash, bell pepper and onion with 1 tablespoon of the olive oil and some salt and pepper. Grill until grill marks appear and the vegetables are slightly tender but still a little al dente, 1 1/2 to 2 minutes per side. Transfer to a cutting board and cut into bite-size pieces.
Brush the naan with the remaining 1 tablespoon olive oil, then sprinkle with the oregano, thyme and garlic powder. Top each piece of naan with half of the grilled vegetables and sun-dried tomatoes. Dollop with the ricotta and season with salt and pepper. Bake until the bread starts to get crispy, 12 to 15 minutes.
Finish with a drizzle of olive oil and a sprinkle of basil and red pepper flakes before serving.