Put conger-pike eel in a deep container and rouse it with salt; Leave it for up to 2 hours to kill it and to remove much of its slime (recommend not to bury it completely in salt); Rinse it thoroughly in cold water and scrape it to remove final traces of its slime; Sprinkle salt on it; Make a cut from its anus about halfway down to the neck end with a filleting knife; Pull away any innards from the rib cage; Scrub the gut cavity and rinse it out carefully to remove all traces of blood from the backbone and throat; Rinse it under running water for 6 minutes; Cut it into sections.
Rinse salted mustard greens under running water; Soak it in water for 10 minutes; Remove it; Squeeze and cut it into stripes.
Rinse, drain, peel and julienne ginger.
Rinse and drain coriander; Cut off any root and most of the stem.
Add 1 tbsp oil, the garlic and the ginger into a nonstick casserole; Stir-fry them over a medium heat till fragrant; Add the eel; Stir-fry over a medium heat for 3 minutes; Add the salted mustard greens; Stir-fry over a medium heat for 1 minute; Add seasonings; Bring to the boil over a high heat; Turn to a low heat; Cook over a low heat for 30 minutes; Turn off the heat; Garnish it with the coriander; Ready to serve.