Stir the soup, soy sauce, vinegar, ginger and garlic powder in a 1-quart saucepan.
Lightly oil the grill rack and heat the grill to medium. Grill the chicken for 15 minutes or until cooked through, turning and brushing often with the soup mixture. Cut the chicken into thin strips.
Heat the remaining soup mixture over medium-high heat to a boil. Arrange the salad greens and chicken on a platter. Serve with the soup mixture.