Soak a cedar plank in very warm water for 1-2 hours.
Prepare coals for grilling—a very hot 450˚F to 500˚F
Combine lime, and orange juice, soy sauce, and garlic on plate. Dip the swordfish in the mixture and let marinate for 6 minutes per side. Sprinkle the fish with chopped parsley and freshly ground black pepper.
Remove the plank from the water, pat it dry.
Place the fish on the plank over a layer of green onions, and then place plank on the grill. Grill until the fish steaks are just opaque in the center and still very moist, about 20 to 25 minutes.