I've put up a list of K3-specific keyboard shortcuts and some other tips at http://bit.ly/k3shortcuts
If you want to keep a copy of them as a book on your Kindle, you can download them as a mobi file (complete with TOC and 'chapter' markers) or as a simpler AZW, direct from you Kindle. The files themselves have links so you can check the website for updates and download updated files from within the 'book' on your Kindle.
This is a work in progress, so further updates are likely. It represents the accumulated knowledge of Kindle users everywhere, so feel free to copy or otherwise use the list as you see fit