In a 6-qt. stockpot, bring 12 cups water to a boil. Add green beans; cook, uncovered, 2-3 minutes or just until crisp-tender and bright green. Quickly remove and immediately drop into ice water. Drain and pat dry. , In a blender or food processor, combine the remaining ingredients; process until well blended. Pour dressing mixture over beans; toss to coat. Refrigerate until serving.