Wash duckling inside and out under running cold water, dry well. Skewer neck skin to the back of the bird, twist the wing tips until they rest flat against the skewered neck skin.Mix soy sauce, sugar, pumpkin pie spice, anise seeds, and ginger in a cup. Rub into the skin and inside the duckling, then pour any remaining mixture into the cavity. Place duck, breast down, on a plate, cover loosely, chill overnight.When ready to roast duckling, mix any sauce on plate with boiling water, pour into body cavity, then close opening tightly with skewers.Place duck, breast side up on a rack in the roasting pan. Do not cover or add any water.Roast in very hot oven (500 F) for 30 minutes, lower heat to slow (350 F). Remove duckling from the oven, dip all fat from the pan with a spoon or baster, then return duckling to oven.Continue roasting, spooning off fat as it cooks out, 1 hour, or until tender. (Drumstick should feel soft and twist and move easily.)Place shredded romaine on a heated serving platter. Remove skewers from duckling, then set duckling on the platter. Cut in four serving size pieces with poultry shears, letting the juices from the cavity flow over the romaine. Serve the duckling at once while the skin is at its crispiest, along with the romaine.