Heat sesame oil in a large skillet over medium heat. Add garlic, and sauté for 2 minutes. Add mushrooms and chicken, and sauté for 6-8 minutes, until meat is no longer pink and mushrooms are tender. Add cabbage, salt, red pepper and water chestnuts, and cook for 5 minutes, until cabbage wilts and liquid has evaporated. Remove from heat, and stir in onions, oyster sauce and soy sauce. Cool slightly, and stir in cilantro.