Toss the onions and cherry tomatoes in some olive oil and place on foil In the grill. Cook for about ten minutes. Grill the pre-made flatbread for a couple minutes on one side while the onions and tomatoes are cooking. Wilt the spinach in a pan while this is happening. After a couple minutes, remove the flatbread from the grill and add the sauce then toppings (wilted spinach, grilled onions and tomatoes, pre-cooked chicken, cheese, and pizza seasoning) and then return the pizza to the grill for about ten more minutes to cook on low heat.