Combine granulated sugar and orange zest in a food processor and pulse until finely ground and fragrant.

Add flour, butter, salt, and orange extract to the mixture. Pulse until combined and a ragged dough forms.

Turn out the dough, divide it in half, and roll into logs. Wrap in plastic and refrigerate for 2 hours.

Preheat oven to 350°F. Slice logs into ½-inch rounds and place on parchment-lined baking sheets. Bake for 10-12 minutes.

Cool cookies on a wire rack. Melt chocolate and dip each cookie halfway, letting excess drip off before setting on parchment.