For dressing: Whisk ingredients until sugar is dissolved. Let stand at room temperature for 15 to 20 minutes to allow flavors to blend.
For salad: Place first 6 ingredients into a large salad bowl and toss gently. Pour dressing over salad and toss again. Refrigerate for 1 to 2 hours. Just before serving, toss once more and top with Chinese noodles. Garnish with lemon slices.