Heat the oil in a 10-inch skillet over medium-high heat. Add the chicken and cook for 10 minutes or until well browned on both sides. Remove the chicken from the skillet. Stir the garlic, vinegar and water in the skillet. Cook and stir for 1 minute. Stir in the soup, tomatoes, olives, if desired, and oregano and heat to a boil. Return the chicken to the skillet. Reduce the heat to low. Cook for 5 minutes or until the chicken is cooked through. Sprinkle with the cheese. Serve the chicken and sauce with the orzo.