Preheat oven to 450ºF. Chop the leaves of the cilantro.
Cook the onion and pepper in vegetable oil over medium heat until they are tender and fragrant, about 3-5 minutes. Remove them from the heat. Combine the cooked, chopped chicken with ½ cup of BBQ sauce.
Lightly dust a clean countertop with flour. Roll the pizza dough to the thinness of your preference. Place the pizza crust on the baking sheet.
In a small mixing bowl, stir ½ cup of barbecue sauce and tomato paste together. Use large spoon or pastry brush to spread the sauce onto the pizza crust. Sprinkle ½ cup of cheese on the crust, followed by the chicken, cooked vegetables, and the cilantro. Sprinkle the remainder of the cheese over the pizza.
Bake the pizza for 10-12 minutes. Check that bottom of the crust has browned and all of cheese has melted before you remove the pizza from the oven.