You could use the unix find command to do this, e.g.
find . -type f -size -71 -exec rm {} \;
will find all files within (and under) your current directory with a size of 71 blocks or less (1 block=512 bytes, so 71 blocks is roughly 36Kb) and remove them.
Bear in mind that this commmand searches directories recursively from the start directory!!
If you just want to list the files it finds first to be sure, you can use the command
find . -type f -size -71 -exec ls -l {} \;
Greg.