Step 1In a medium bowl, combine the onion, preserved lemon, garlic, parsley, dill and chile flakes. Add the Champagne vinegar and mix well to evenly distribute. While whisking, slowly drizzle in the oil. Season to taste with the salt and pepper. This makes a scant cup vinaigrette, more than enough for the remainder of the recipe. The vinaigrette will keep, covered and refrigerated, for up to 5 days.
Step 1Place the shaved asparagus and onion in a bowl and add about 4 tablespoons vinaigrette, tossing to coat. Set aside for a few minutes to soften the asparagus and onion.
Step 2Meanwhile, divide the coppa between 2 plates.
Step 3Take the marinated asparagus and onion (it should be pliable like firm noodles), gently twist them into a little nest and place atop the coppa. Garnish with shaved Parmigiano. Serve immediately.