Sure there is.....
start>run>mstsc /span
Need both the target and the host ot have the same configuration though......
For your situation though....
Look in My Documents for the default.rdp file.....
Edit the following....
desktopwidth:i:1280
desktopheight:i:1024
Your width is probably at 2560 (or similar, but you get the idea..)
Then save it...