1In small bowl, mix sauce ingredients with wire whisk until well blended; set aside.
2In wok or 12-inch nonstick skillet, heat 1 tablespoon of the oil over high heat about 2 minutes. Add chicken, onion, garlic and gingerroot, breaking up clumps of chicken with wooden spoon; cook 1 minute without stirring. Stir-fry about 3 minutes or until chicken is no longer pink in center. Transfer chicken mixture to clean bowl.
3To empty wok, add remaining 1 tablespoon oil; heat over high heat about 1 minute. Add green beans and bell pepper; cook 2 minutes, stirring frequently. Add water; cover and cook 1 to 2 minutes. Stir vegetables.
4Return chicken mixture to wok. Mix sauce mixture again with wire whisk to recombine; pour into wok. Stir to coat mixture with sauce. Cook uncovered about 1 minute or until sauce is thickened. Stir in pineapple and peanuts.