Break off woody asparagus where spears snap easily; scrape off scales. Wash asparagus. Place a steamer basket in a saucepan. Add water to just below the bottom of the steamer basket. Bring to boiling. Add asparagus. Cover and reduce heat. Steam for 4 to 8 minutes or until crisp-tender.
Meanwhile, for sauce in a small saucepan combine sour cream, mayonnaise or salad dressing, lemon peel, and lemon juice. Stir in enough milk (1 to 2 teaspoons) to make of desired consistency. Cook and stir over low heat until heated through, but do not boil. Serve over asparagus. Garnish with lemon peel strips, if desired. Makes 6 to 8 servings.