Preheat your grill to medium-high heat (about 450°F/230°C).
Grill the vegetables: Brush the zucchini, summer squash, and eggplant slices with olive oil and season with salt and pepper.
Place the vegetable slices on the grill and cook for about 3-4 minutes per side, until tender and grill marks appear.
Remove from the grill and set aside.
Close the grill and preheat to 500 degrees. On a lightly floured surface, roll out the whole wheat pizza dough into a long, thin oval shape. Brush one side of the dough with olive oil. Place the oiled side down on the grill. Close the grill, Cook for about 2-3 minutes, until grill marks appear and the dough begins to puff up. Flip the flatbread and grill for another 2-3 minutes.
Remove the grilled flatbread from the grill and place it on a large cutting board or serving platter. Spread a layer of red pepper hummus over the flatbread. Arrange the grilled zucchini, summer squash, and eggplant slices on top. Sprinkle with fresh marjoram leaves and crumbled feta cheese. Drizzle with hot honey to taste and add black pepper. Cut the flatbread into slices and serve immediately. Enjoy