From: A Very Chinese Cookbook
Process soy sauce, sesame paste, sugar, vinegar, 1 tablespoon water, chilli oil, garlic, and ginger in blender until smooth, about 30 seconds, scraping down sides of blender jar as needed; transfer to large bowl.
Meanwhile, bring 4 quarts water to boil in large pot. Add noodles and cook, stirring often, until just tender. Drain noodles and rinse under cold running water until chilled; drain well.
Transfer noodles to bowl with dressing and toss to combine. Adjust consistency with extra water as needed until sauce smoothly coats noodles. Transfer noodles to shallow serving bowl and top with cucumber, cilantro, scallions, and sesame seeds. Serve.
