Place potatoes and water to cover in a large saucepan; bring to a boil over medium heat, and cook 13 minutes. Add green beans, and cook 7 minutes or until potatoes are tender; drain. Rinse with cold water. Cut each potato into 8 wedges.
Whisk together vinegar and next 6 ingredients in a large bowl; add potatoes and green beans, gently tossing to coat. Cover and chill at least 2 hours.