Toast hazelnuts at 350˚ for 7 minutes. Remove skins with a paper towel. Peel and cube squash and place on a baking sheet. Drizzle with olive oil, and sprinkle with salt and pepper. Roast at 400˚ for 30 minutes or until tender. Place farro in a pot with 3 cups of water. Bring to a boil, cover, and simmer for 25 minutes. Drain and set aside to cool. After squash and farro have cooled, add to a large bowl with remaining salad ingredients. Place all dressing ingredients in a blender, and blend until combined. Toss with salad.