Snap off rough ends of asparagus.
Remove scales from stalks, using a knife or vegetable peeler, if desired.
Arrange spears in a large skillet; add 1/2 cup water, and bring to a boil.
Cover, reduce heat, and simmer 6 to 8 minutes or until crisp-tender.
Drain and set aside.
Melt margarine in a small saucepan over low heat, add flour, stirring until smooth (mixture will be dry).
Cook 1 minute, stirring constantly.
Gradually stir in milk; cook over medium heat, stirring constantly with a wire whisk, until mixture is thickened and bubbly.
Remove from heat, stir in Swiss cheese, horn, onion, mustard, and pepper, stirring until cheese melts.
Place 2 asparagus spears in center of each crepe.
Spoon 2 tablespoons ham mixture over asparagus; roll up, and place seam side down in a 10- x 9- x 2-inch baking dish coated with cooking spray.
Sprinkle with Parmesan cheese and paprika.
Broil 4 to 5 inches from hearing element 2 minutes or until golden.