Toss all ingredients into a large bowl. Drizzle with desired amount of dressing and toss. Serve immediately.
For the Dressing:
In a blender, combine sugar, vinegar, onion, mustard, and salt. Puree until smooth. While mixing on low speed, slowly stream in the oil, mixing until creamy. Add the poppy seeds and mix until combined.
Place in a jar and store in the fridge.
Toast pecans for 10 minutes on a baking sheet at 350 degree F.