It might help if you tell us a bit more about what specific kind of training you are looking for.
I just had a look and apparently there is no forum for the mapper community in Tunisia, and the mailing list appears to be unused. But you could check who is mapping in Tunisia and contact those mappers directly? Or contact mappers in neighboring countries; the forum for mappers in Algeria and the mailing list for Morocco seem to have some users.
OpenStreetMap
Discussion
Comment from lyx on 19 December 2015 at 21:02
It might help if you tell us a bit more about what specific kind of training you are looking for. I just had a look and apparently there is no forum for the mapper community in Tunisia, and the mailing list appears to be unused. But you could check who is mapping in Tunisia and contact those mappers directly? Or contact mappers in neighboring countries; the forum for mappers in Algeria and the mailing list for Morocco seem to have some users.