Hi Marek,
Many thanks for supporting Push to Kindle development. Really appreciate it.
It’s possible to assign a keyword shortcut to bring up the preview screen in both Chrome and Firefox. By default Alt+Shift+K, but you can change these in both browsers. In Chrome by entering chrome://extensions/shortcuts in the address bar.
I assume you want a keyboard shortcut that will send the article as well. We’ve had a few requests for that, so will be looking into it for future releases.
Thanks again!