Chubby Hubby - Steamed fish Hong Kong style

Ingredients

• 1 whole fish 600-800g, or 1-2 fish steaks
• sea salt
• 4 spring onions
• 2 slices ginger
• 1 cm thick piece of ginger
• 1 large sprig of coriander, root intact if possible
• 2 tbs light soy sauce
• 1/2 tsp castor sugar
• 2 tbs water
• 2-3 tbs cooking oil