Preparation Working in 3 batches, cook green beans in a large pot of boiling salted water until crisp-tender. Transfer to a large bowl of ice water to cool. Drain well. Trim beans; cut in half on a sharp diagonal. DO AHEAD: Can be made 8 hours ahead. Arrange cooked beans in batches in paper towels, roll into cylinders, and transfer to plastic bags; seal and chill. Whisk miso, 2 tablespoons scallions, vinegar, mustard, oil, and sugar in a small bowl. Season dressing to taste with salt. Place green beans in a large bowl. Pour dressing over; toss to coat. Garnish with almonds and remaining 1 tablespoon scallions. Serve warm or at room temperature.
Preparation Working in 3 batches, cook green beans in a large pot of boiling salted water until crisp-tender. Transfer to a large bowl of ice water to cool. Drain well. Trim beans; cut in half on a sharp diagonal. DO AHEAD: Can be made 8 hours ahead. Arrange cooked beans in batches in paper towels, roll into cylinders, and transfer to plastic bags; seal and chill. Whisk miso, 2 tablespoons scallions, vinegar, mustard, oil, and sugar in a small bowl. Season dressing to taste with salt. Place green beans in a large bowl. Pour dressing over; toss to coat. Garnish with almonds and remaining 1 tablespoon scallions. Serve warm or at room temperature.