For the crust, combine ingredients and pat down into a 9-inch pie pan. Bake for 5 to 10 minutes.
For the filling: In a medium bowl, combine the milk, lime juice, and 1 teaspoon zest; blend in the egg yolks. Pour the filling into the crust.
For the meringue, beat the egg whites with the cream of tartar until soft peaks form. Gradually beat in the sugar and remaining teaspoon zest until the mixture is stiff. Spread the meringue over the filling; spread it to touch the edge of the crust all around. Bake for 12 to 15 minutes, or until the meringue is golden brown.