With a sharp knife, remove the duck’s skin and fat in order to leave only a thin layer.
In a glass dish, combine the green onion, lemon juice, harissa, and spices. Add the meat and coat thoroughly. Season with salt. Cover and refrigerate for 12 to 24 hours.
Preheat half the grill, setting the burner on high. Oil the grate.
Place the duck breasts, fat side down, on the off section the grill. Cook for about 15 minutes. Grill the duck breasts on the lit section for 3 to 4 minutes per side or until the desired doneness. Delicious with Potato and Onion en Papillotes.