In a large bowl, whisk together the marinade/dressing ingredients until sugar dissolves. Add the drained noodles to the dressing and toss until pasta is coated evenly with dressing. The pasta will not immediately absorb all the dressing; cover the bowl with plastic wrap and place noodles in the fridge for about 15 minutes then toss noodles again to ensure dressing is distributed evenly and continues to be absorbed by the noodles. Cover and store in the fridge for another 15 minutes and then toss once more. Store in the fridge covered until ready to serve. I recommend making the noodles at least 2 hours ahead of serving so dressing flavors can fully incorporate. When ready to serve, transfer noodles to a serving bowl or platter. Toss together the garnish ingredients with the reserved dressing and spread on top of the noodles.
Other Options for Garnish:
Fresh shiitake mushrooms, finely sliced
Fresh snow peas, finely sliced across a diagonal