Put cabbage and onion into a bowl, sprinkle with salt, and let stand 10 minutes.
Squeeze out liquid.
Fry salt pork in a skillet until golden.
Add cabbage-onion mixture and wine.
Cover and simmer 20 minutes.
Place duck in a roasting pan.
Bake at 425Â°F 30 minutes.
Drain off fat.
Spoon cabbage mixture over duck.
Reduce oven temperature to 350Â°F.
Bake about 45 minutes, or until duck is tender.