In a medium bowl, whisk together the flour with the salt.
In a small bowl, combine the sugar with the orange zest. Use your fingers to combine the zest into the sugar. Set aside.
In a large mixing bowl, mix the butter on high speed for about a minute. Add sugar and the vanilla extract. Continue to beat until light and fluffy, about 2-3 minutes. Add the flour and stir in until just about combined.
Divide the dough into two portions. Wrap each dough ball in plastic wrap and put it in the fridge for about 1/2 hour to chill.
Preheat oven to 350 degrees F. Line two baking trays with parchment paper.
On a lightly floured surface roll out the dough to about 1/2 inch thick. Using 2 inch circle cookie cutters, cut out as many as you can from each disk. Dough can be re rolled and cut again. Chill unbaked cookies for 5 minutes.
Bake chilled cookies for about 12 – 15 minutes. Remove from oven and place on a wire rack to cool completely. Don’t let the cookies brown. If you notice the edges start browning, remove from the oven.
Place the chocolate in a double boiler set over simmering water. Stir until it melts. This will take about 3 minutes or so.
When the cookies have cooled, dip them in the melted chocolate. Place dipped cookies on a baking rack. Immediately sprinkle over extra orange zest of topping.
Allow the chocolate to dry completely, this will take about one hour. Once set, they can be stored in an airtight container between parchment paper.