Trim excess fat and skin from duck and save for rendering. Score the skin of the duck with a small sharp paring knife, just shallow hatch marks through the skin, not piercing the meat.
Grind the peppercorns and fennel together. Combine with the salt, coriander, paprika and the orange zest.
Rub this mixture thoroughly onto the outside and inside of the duck.
Squeeze the orange juice into a small bowl and then tuck the orange halves and rosemary into the cavity of the duck.
Place breast-up on a rack in a roasting pan and refrigerate uncovered 2 hours and up to 24 hours.
Set oven to 450ºF
Place duck in oven and immediately REDUCE heat to 350º.
Roast for 20 minutes per pound or until the temperature measured in the thigh is 165ºF.
Remove from oven and INCREASE the oven temperature to 450ºF.
Use a turkey baster to remove as much of the fat from the pan as you can. Save this for other uses.
Combine glaze ingredients and brush liberally over the duck.
Return to oven for 15-20 minutes longer or until the temperature in the thigh is 180ºF.
Rest for 15-20 minutes before carving as you would a chicken.
Remove from oven and allow to rest, uncovered, for 20-30 minutes.