This article is filled with link of clans that only have a few weak ninjas that are meant for you to kill easilly at almost any level. Just click on the profile link and you will go to their profile page and you can battle them. Feel free to add more link or change the levels of the existing ones. Just make sure to keep them in order by level.
Please not that some of them have 2 or 3 ninjas or their ninja has a weapon. If you are in the low levels check what the ninjas have first, or you may lose.