Kill process by name and owner?
Solution 1:
In powershell you would do:
gwmi -query "select * from win32_process where name='PROCESSNAME.exe'" | %{if($_.GetOwner().User -eq 'USERNAME'){$_.terminate()}}
Solution 2:
You weren't looking hard enough.
taskkill /f /fi "imagename eq foo.exe" /fi "username eq Chris"
You can even filter by modules loaded, using /fi "modules eq libfoo.dll".