Preheat oven to 375°F. Toast hazelnuts in a small shallow baking pan until golden, 4 to 5 minutes. Trim woody ends from asparagus and, if desired, peel lower 2 inches of stems with a vegetable peeler. Cook asparagus in a large saucepan of boiling salted water until crisp-tender, about 6 minutes, and drain well in a colander. Whisk together remaining ingredients except nuts with salt and pepper to taste. Transfer hot asparagus to plates. Spoon orange dressing over top and sprinkle with nuts.