Need Help Executing a Remote Task from SQL Server Agent
I have only done this a couple of times and quite a while ago.  At that time I used PSEXEC.EXE from the Windows Internals.  You can read the instructions here:

http://technet.microsoft.com/en-us/sysinternals/bb897553.aspx

For Powershell remote execution there was a discussion in StackOverflow that satisfied the questioner.  Powershell is probably the way to go these days.

https://stackoverflow.com/questions/9535515/powershell-execute-remote-exe-with-command-line-arguments-on-remote-computer

However you run the remote job, you can schedule it in the SQL Server Agent process that runs the other jobs.   If you think it would work for you, you could also set the job to run on a defined period of 'idleness'.  (I don't think that is what you want, but you can look into it under the SQL Server Agent discussion on Agent schedules at http://technet.microsoft.com/en-us/library/ms189065.aspx.)