Snap off the tough ends of the asparagus (can freeze and save for soup).
Using a sharp vegetable peeler, shave the asparagus lengthwise into paper-thin ribbons
In a small jar, shake together the lemon juice, olive oil, and Dijon mustard to make a dressing.
Season to taste with salt and pepper
Arrange shred on a serving platter
With a vegetable peeler, shave thin curls of Parmesan over the salad. Accompany with an optional handful of toasted pine nuts or crisped prosciutto, or garnish the platter with arugula leaves.