Combine gingersnap crumbs and margarine in a small bowl; mix well.
Press mixture evenly on bottom of a 12-inch pizza pan coated with cooking spray.
Bake at 375° for 5 minutes.
Remove tart shell from oven, and cool completely.
Combine cheese, sugar, lemon rind, and 1 tablespoon lemon juice in a small bowl; beat until well blended.
Spread mixture evenly over cooled crust.
Set aside.
Combine orange juice, 2 tablespoons lemon juice, and cornstarch in a non-aluminum sauce- pan, beat with a wire whisk unril well bended.
Bring to a boil.
Cover; reduce heat, and cook until mixture thickens, stirring frequently with wire whisk.
Remove glaze from heat, cool.
Dip pear slices in remaining 2 tablespoons lemon juice; drain well.
Arrange pear slices over tart.
Drizzle glaze over pears.
Cover, chill tart thoroughly.
Cut into wedges to serve.