Place red and sweet potatoes in large saucepan; add enough water to cover. Bring to a boil. Reduce heat; cover and simmer 20 to 25 minutes or until potatoes are tender.
Meanwhile, heat kielbasa in medium nonstick skillet over medium heat for 5 minutes or until browned, stirring and turning slices frequently. In small bowl, combine water and flour; mix well. Add flour mixture, onions, sugar, vinegar, salt and pepper to kielbasa in skillet; stir to mix well. Bring to a boil. Cook 1 minute, stirring occasionally.
Peel potatoes; cut into cubes. Place in medium bowl. Pour kielbasa mixture over potatoes; mix well.