In slow cooker, place carrots, celery, green pepper and onion. Top with chicken breasts. Sprinkle with salt. Pour sweet-sour sauce and pineapple chunks over all. Cover. Cook on low 7 to 8 hours or high 3 1/2 to 4 hours.
Remove chicken, keeping it warm. Blend cornstarch and water, stir into juices in slow cooker/Crock Pot. Cover; cook on high 10 to 15 minutes or until thickened. Season to taste and serve over rice.