in reply to File::Find seems grossly inefficient for performing simple file tasks
Did you mean programmer efficiency?
File::Find::Rule has a nicer interface and is easier to use (IMHO).
So your query could look something like this :-
my $uid = getpwnam('web');
my @files = File::Find::Rule->file->name('*.iso')->uid($uid)->in('/');
unlink $_ for @files;
There are methods for the stat tests, ctime,size etc, so you can add more stages as you need them. I'm not sure what 'find -cmin' actually does so I didn't attempt that bit.