1. Empty coconut into pie plate, 9 x 1 1/4 inches; reserve 1/2 cup for filling. Microwave remaining coconut in pie plate uncovered on high 4 to 6 minutes, stirring every 30 seconds, until brown. (Watch carefully so coconut does not burn.) Remove 2 tablespoons of the toasted coconut; reserve for top of pie.
2. Toss remaining coconut and margarine until coconut is well coated. Press mixture evenly against bottom and side of pie plate. Microwave uncovered 1 minute; cool.