The PsFile command allows you to list files opened remotely on a computer, and optionally close them. See the PsFile topic in the PsTools help file for more details.
"List all files"
Select this option to have PsFile list all open files on the specified computer.
"List files matching..."
Enter a PsFile ID, or a (partial or complete) pathname, in order to just list certain files. Check the "Close the specified file" box to force-close any files which match.
See the PsTools Common Options topic.