In a large skillet, heat the 1 tablespoon of olive oil over medium heat.
Add the diced onion and diced green bell pepper to the skillet. Sauté for about 3-4 minutes, or until tender.
Stir in the minced garlic and cook for an additional minute. Then, add the ground chicken, breaking it apart. Cook until browned, about 5-7 minutes.
Sprinkle the kosher salt and chili powder over the chicken mixture. Stir well.
Pour in the ketchup, mustard, tomato paste, Worcestershire sauce, and water. Stir until combined.
Reduce the heat to low and let the mixture simmer for about 10 minutes.
Spoon the mixture onto the hamburger buns and serve hot.