Place potatoes in medium saucepan; add enough water to cover. If desired, add small amount of salt to water. Bring to a boil over medium-high heat. Cook 8 to 10 minutes or just until tender. Drain. Cool potatoes 30 minutes.
In refrigerator storage bowl, combine cooled potatoes and all remaining ingredients; mix gently. Cover; refrigerate at least 2 hours to blend flavors.