Combine water and onions in large skillet; bring to boil over medium heat. Add chicken, cover, reduce heat, and simmer 15 minutes or until cooked. Remove chicken, set aside and let cool. Discard cooking liquid, shred chicken into bitesized pieces and set aside.
Combine wine and next nine ingredients in large heavy duty zip top plastic bag. Add chicken, seal bag, and marinate in refrigerator for two hours, turning bag occasionally. Drain, discard marinade.
Combine chicken, pineapple, grapes, and mayonaise in a bowl and toss gently. Serve on a lettuce plate if desired. Top with sliced green onions.