Preheat oven to 350 degrees. Spray or grease a 9-inch square baking pan.
In a large bowl, combine 1 cup of flour, the confectioner's sugar, the salt and butter. Cut butter into flour mixture until it resembles coarse meal. Press into prepared baking pan. Bake for 20-25 minutes, or until edges begin to turn light brown.
While crust is baking, prepare filling--in a medium bowl, combine the remaining 1/4 cup of flour, the sugar, and the orange zest. Beat in eggs, 1 at a time, combining well. Beat in the orange juice and add food colorings (these are optional).
Prepare crumbs--in a small saucepan, melt the butter. Add the sugar and orange zest. Add the flour and mix until it forms a nice, dense crumb--you may have to add additional flour. Add additional flour by tablespoons full until desired consistency is achieved. Stir in the coconut.
When crust begins to turn light brown, pour filling over crust. Bake for 15 minutes (or until slightly set). Top with the crumb mixture and bake an additonal 15-20 minutes or until filling is set (it will feel firm to the touch in the center) and crumbs are golden brown.
Remove from oven and top with chocolate chips. Cool completely, then chill before serving.
Makes 9 large bars.
**You may need more flour