Whisk together the miso, mirin, vinegar, soy sauce, green onions, ginger, and sesame oil in a small bowl. Place the salmon in a baking dish or plastic bag, pour the marinade over, and turn to coat. Cover and marinate for 30 minutes in the refrigerator.
Heat grill pan to medium-high. Remove the fish from the marinade and season with salt and pepper. Grill the salmon, skin side down, until it is golden brown, about 3 to 4 minutes. Turn the salmon over and continue grilling for 3 to 4 minutes for medium doneness. Drizzle with a little yuzu or orange juice and serve.
Cook on the Grill
Grill the salmon, skin side down, with the cover closed, until it is golden brown and a crust has formed, about 3 to 4 minutes. Turn the salmon over and continue grilling for 3 to 4 minutes for medium doneness.