1. Combine all the ingredients for the rub except the kosher salt and olive oil.
2. Trim most of the fat from the duck breasts leaving a thin covering of fat. Carefully score fat making sure not to cut into the flesh. Pat duck dry with paper towels.
3. Two hours before cooking remove duck breasts from fridge, rub with olive oil and then spice mixture. Wrap tightly and allow to sit for about an hour to come to room temperature.
4. 4. Preheat grill to medium. Season duck with Kosher just before grilling. Grill duck fat side down for 5 minutes, be careful of flare ups due to dripping fat. Flip duck and grill on other side for 3-5 minutes. Duck is best served a little pink inside since there is not a lot of internal fat and it tends to dry out if cooked longer.
5. Let rest for 3-4 minutes. Slice thinly, serve and enjoy!