Why not just set "Allow users to run the program independently of assignments" in the advertisement? Then the users can run them from the Run Advertised Programs applet in the Control Panel.
Otherwise, for remote cases, you can just use PSEXEC from Sysinternals and use "-s" to run the program in the SYSTEM context like SCCM/SMS does.
Example:
psexec -s \\somecomputer \\yoursmsserver\c$\SMSPKGC$\0010003D\somefile.exe
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