bonjela works nicely. though i feel it tastes weird. 
usually people get ulcers in the mouth due to a small
cut (caused by biting, or sharp food particles) and the cut gets
infected with bacteria. that is why salt works to speed up healing.
cos when u put salt, the bacteria gets dehydrated, and probably
die. then your white blood cells will just go and clean up the
debris.
of cos, that may be too much details. bottom line is, use bonjela.
