Preheat oven to 350 degrees F (175 degrees C). In a large bowl, mix the noodles, sunflower seeds, and pine nuts with melted butter until evenly coated. Spread the mixture in a thin layer on a baking sheet.
Bake 7 to 10 minutes in the preheated oven, stirring occasionally, until evenly toasted. Remove from heat, and cool slightly.
In a large bowl toss together the noodle mixture, bok choy, green onions, chicken, water chestnuts, and snow peas.
Prepare the dressing by blending the oil, vinegar, soy sauce, sugar, and lemon juice. Pour over salad, and toss to evenly coat. Serve immediately, or refrigerate until chilled.