this really depends on the server. Usually -l and -a (or -la) are used, but there can be many more (such as -d).
I think they correlate with switches for 'ls' command on UNIX (well, more or less) so perhaps you want to read helpfile on some UNIX system for that command?
I am not sure what your question is. ListDir always requests directory listing from one directory. It cannot go into subdirectories at all. Why do you think it can? What results did you get?
If remote side is UNIX, and you use '-alR' switch then, hmm, perhaps you would go into subdirectories - but I am not sure that is the case.