Fry the salt in a dry wok for a few minutes until aromatic.
Place the pork, fish sauce and salt in a food processor and pulse until it forms a very fine paste.
Soak the banana leaf in water for 5 minutes, dry and lay it flat on a bench.
Cut the leaf in 1/2 and cross 1 piece over the other.
Place the pork paste in the center and draw up all sides to form a tight parcel. Secure with string and cook in simmering salted water 1 hour.
Allow to cool, remove the banana leaf and slice the pork and place into baguettes together with cucumber, coriander, spring onions, chile, pinch of salt and pepper and light soy sauce.