Cook the noodles in large pot of boiling salted water over medium heat until barely tender and still firm. Drain immediately and rinse with cold water until cool. Drain the noodles well and transfer to a wide bowl.
In a blender, add the ginger, garlic, sugar, peanut butter, vinegar, soy sauce, chili sauce, sesame oil, and water. Process until the mixture is smooth. Put the blender jar into the refrigerator and let it chill for about 1/2 hour. Pour the peanut sauce over the noodles and toss until well coated. Serve garnished with the scallions, sesame seeds, and cilantro.