Rinse dried shiitake mushrooms under running water; Soak them in water for 3 hours; Remove and drain them; Discard the stems with a pair of kitchen scissors; Shred the remaining with a vegetable knife.
Hold a flathead mullet firmly by the head and scrape the scales from the tail towards the gills with a fish scaler; Rinse the fish under running water; Insert the knife into the anus near the tail; Draw the knife toward the head, splitting the fish to the base of the gills; Spread the abdominal cavity with fingers; Reach in and pull out the entrails; Rinse the cavity under running water; Cut off the head with the knife; Rinse the fish under running water again; Pat-dry the fish with kitchen paper; Rub seasoning (1) into the fish; Leave it for 30 minutes.
Add seasoning (2) into a mixing bowl; Mix.
Rinse fat pork under running water; Pat-dry it with kitchen paper; Julienne it; Marinate it with the seasoning (2) for 30 minutes.
Rinse and drain spring onion; Cut off any roots; Julienne it.
Rinse, drain, peel and julienne ginger.
Rinse and drain a red chili pepper; Slice off any stem with a vegetable knife; Bisect it lengthwise; Scrap any seeds out; Julienne it.
Discard any seeds of a salted lemon; Julienne it.
Add seasoning (3) into a mixing bowl; Mix.
Fill a wok with water; Stack a bamboo steamer in the wok; Bring to the boil over a high heat.
Arrange the flathead mullet on a steaming plate; Evenly lay all other remaining ingredients on the mullet; Drizzle the seasoning (3) over the mullet; Arrange the steaming plate in the bamboo steamer; Steam over a high heat for 13 minutes; Turn off the heat; Ready to serve.