As far as I know, the only way to get to this information is through P/Invoke calls to NtQuerySystemInformation. Most of the API required to perform this task is only loosely documented, so good luck!
There is an excellent discussion
here that may help you achieve what you want.
However, killing off a process that has an open file handle is obviously not a recommended practice. Depending on what is being done with the file at the time your possibly risking corruption. If there is any other way to achieve what you want, I'd probably do that instead.