Peel pears and core from bottom, cutting to, but not through, stem end.
Combine orange juice, liqueur, and orange rind in a large Dutch oven; bring to a boil.
Place pears, stem end up, in Dutch oven; paste pears with juice mixture.
Cover, reduce heat, and simmer 10 to 15 minutes or until pears are tender.
Remove pears with a slotted spoon; place in dessert dishes, and set aside .Combine cornstarch and water,- stir well.
Add cornstarch mixture to juice mixture; cook over low heat, stirring constantly, until thickened.
Pour orange sauce evenly over pears.