City-style salmon served over a fragrant slab of cedar.
Let the planks soak in warm water for at least an hour, though a little extra time wouldn't hurt.
Stir together the vegetable oil, rice vinegar, sesame oil, soy sauce, green onions, ginger, and garlic in a shallow dish to create a marinade. Place the salmon fillets in the marinade and turn them around to get an even coat. Put a cover over the dish and let the fish marinate for at least 15 minutes, or up to an hour.
Fire a grill up to medium heat and place the prepped planks on the grate. You want these things to be ever so slightly smoking and crackling to get that cedar scent out there.
Place the marinated fillets onto the planks. You can ditch the marinade now. Put the cover on the grill and grill for about 20 minutes. When you can flake the fish with a fork, you're all done. The fish'll continue cooking for a few minutes on the planks after you take them off the grill; that's normal.