1. Preheat oven to 450 degrees. Line a rimmed 16-by-12-inch baking sheet with foil and coat with cooking spray. Sprinkle flour onto a cutting board and dust both sides of pizza dough with flour. Slowly stretch dough on the back of your knuckles, rotating dough and stretching it out into a rectangular shape to fit the baking sheet. When dough is stretched to about 12 inches, place on the baking sheet and stretch further, using your fingertips.
2. In a small bowl, combine hemp seeds and Parmigiano-Reggiano. Sprinkle mixture over dough, pushing into dough. Scatter mozzarella over dough and dot with ricotta cheese. Place pears on dough in four vertical layers side by side (as close together as possible), pressing pears into dough. Drizzle with lemon juice and maple syrup. Bake 15 to 20 minutes until flatbread is golden brown and pears are cooked. Let cool slightly before serving.