MoinMoin, a python-based wiki works well on the tablets via a browser. MoinMoin currently stores your data in files so all that is required is python.

For tiddlywiki, I tried a GTD variant (getting things done) - GTD Monkey - and couldn't figure out a way to get rid of the security warnings when saving to disk, with the built-in browsers and some of the others I tried.

(Note that easydebian or something else that runs Firefox should work, because it lets you choose to have it remember your preference for letting the page save a modified version of itself back to disk).