How can I find the seminal work (i.e. authors and papers) in an area? 
For example I would like to know which authors and research papers are
thought of as the main or major papers in the area of knowledge
management? I would think that these would be the papers that are
cited most often and these papers would be what most of the other
research in the area of knowledge management is based on.

If you are attached to a university, yo can go to the library and get
an Athens account for online information services.  They should be
able to give you more info, but there are services that give you the
number of times a book is cited.  You could go to Worldcat for
instance and search for knowledge management.  You should be able to
dig up subject categories that fit with what you are looking for
these.  Then you need to search through and see which are the works
most held by libraries worldwide, and additionally which are the most
cited. You could pay for membership to a local university library if
you are not attached to one.  Alternatively you could search the web
for universities teaching knowledge management, contact the lecturers
and ask them very nicely if they will give you a copy of their reading
list. This is what is called doing a literature review, and university
librarians are the best people to help you with this.