Never cooked farmed duck but for wild I do the following
Brine overnight (you might shorten or skip since not wild)
Rinse
Very very light dusting of homemade kc rib rib. Very light!
Smoker at 175 or so until just firming up. Doesn’t work so well at higher smoke temps like 225. Bigger farmed breasts might tolerate better.
Pull off and eat hot sliced thin.