If you means header part - there is one way to hide it (as I understood):
set appropriate size for each column to fill all table width, so
"invisible part" will be located over the table border. As SWT is the
platform-dependent toolkit, possible answer may be found in the underlying
systems documentation, e.g. Win32 Header Control docs:
http://msdn.microsoft.com/en-us/library/bb775238(VS.85).aspx