Prepare Flatbread Dough; let rise and shape into 4 ovals on baking sheets as directed. Cover and set aside.
Preheat oven to 475°.
Heat a medium nonstick skillet coated with cooking spray over medium-high heat. Add corn, squash, jalapeño, and 1/4 teaspoon salt. Cook 3 minutes, stirring frequently. Add onions; cook 1 minute, stirring constantly. Remove from heat; sprinkle with 1/4 teaspoon salt and white pepper. Stir in 3 tablespoons cilantro. Divide the vegetable mixture and cheese evenly among 4 flatbread dough ovals. Bake the flatbread at 475° for 12 minutes or until crust is browned. Sprinkle with remaining cilantro.