Spicy Orange Soba Noodles

Bring a large pot of water to a boil. Add soba noodles and cook until just tender, 6 to 8 minutes; drain, rinse in cold water until cool, and drain again. Meanwhile, in a small saucepan, bring orange juice to a boil. Reduce heat to medium and simmer gently until syrupy and reduced by half, about 15 minutes. Combine orange syrup, soy sauce, sugar, vinegar, and oil in a blender and mix; transfer to a large bowl. Add noodles and scallions; toss well. Serve at room temperature or chilled.