Combine the coconut, 3/4 cup flour, 1/2 cup confectioners' sugar, 1 tbsp cornstarch and butter and mix until a crumbly dough is formed. Press fimly into a greased 8x8" pan. Bake just unil golden, about 12 minutes.
Sift together the granulated sugar, the remaining 1 tbsp cornstarch and 2 tbsp of flour.
In a separate bowl, beat the eggs, lime zest, lime juice and vanilla. Slowly pour the egg mixture into the flour mixture, whisking to avoid lumps. POur the filling over the baked crust.
Bake until the lime curd is set in the center, about 22 minutes. Cool completeley in the refrigeratr, about 2 hours. Cut into 16 bars and dust with powdered sugar before serving.