Score snapper slicing several bias cuts into the flesh, approximately 2 inches apart, on both sides. Season both sides lightly with sea salt and Ponzu, taking care to season inside the scoring. Line a bamboo steamer basket (or similar perforated pan) with large leaves of Napa cabbage. Place snapper directly on cabbage leaves. The cabbage will keep the fish moist while steaming and will help to lift the fish from the steamer basket after being cooked.
Season the topside of the fish generously with fermented black beans and fresh ginger and steam for 10 to 12 minutes, depending on size. The flesh will be opaque when done.
Carefully remove fish by lifting the cabbage leaves and transfer to a very hot metal serving platter.
Top the fish with approximately 2 cups vegetable salad and pour heated soy sauce over the top to wilt the salad and sizzle the platter.
The best way to serve the whole fish is family-style, and for guests to each take some of the salad and pick bite-sized pieces of the soft and succulent fillets.