Cook tortellini according to package directions. Add asparagus and sweet pepper the last 2 minutes of cooking. Drain. Rinse tortellini & vegetables with cold water. Drain again.
For dressing, in a screw-top jar combine lemon peel, lemon juice, oil, mustard, sugar, salt and garlic. Cover. Shake well. Refrigerate.
In a large bowl place tortellini & vegetables. Add dressing and toss to coat. Cover and chill 2-8 hours.
Just before serving stir in cheese, green onions and pine nuts.