Scan row keys only?

[Geoff Hendrey]

Hi,
 
Is it possible to Scan only the row keys, without bringing back any
columns? 
Is it possible to "skip" ahead N rows (rather than retrieving the next N
rows)? 
 
I am trying to do the most efficient possible scan of a huge table, in
order to make splits for a TableInputFormat.
 
-geoff