1. Whisk together first 6 ingredients. Add salt and pepper to taste.
2. Cook green beans in boiling salted water to cover, stirring occasionally, 3 to 4 minutes or until crisp-tender; drain. Plunge into ice water to stop the cooking process; drain.
3. Pat beans dry with paper towels. Place beans and orange segments in a zip-top plastic freezer bag; add vinaigrette, and seal bag. Turn bag to coat beans and oranges. Chill 2 hours. Sprinkle with pecans before serving.