Mix together the sesame seeds and salt. Season the cavity of the fish then make 3 diagonal slashes across each side of the bass so it cooks evenly.
Transfer the fish to a large roasting tin and brush with a little oil. Scatter over the sesame salt and roast for 25-30 minutes until the fish is cooked and lightly golden.
Meanwhile, splash a little sunflower oil into a small pan and cook the ginger, garlic and chile for 2 minutes, without browning. Add the soy sauce, vinegar and sesame oil and remove from the heat.
When the fish is cooked, transfer to a large serving platter. Pour over the ginger dressing, then scatter over the salad onions and coriander leaves. Serve immediately with lime wedges for squeezing over.