To prepare cookies, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and granulated sugar in a bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal.
Press mixture into a 9-inch square baking pan coated with cooking spray. Bake at 350° for 10 minutes.
Combine brown sugar, 3 tablespoons juice, and eggs in a medium bowl, stirring with a whisk. Stir in coconut; pour evenly into pan. Bake an additional 25 minutes or until set.
To prepare glaze, combine powdered sugar, rind, and 2 tablespoons juice, stirring with a whisk. Spread glaze evenly over cookies. Cool completely in pan on a wire rack. Cut cookies into squares.