Can I turn the word coloring off?
I’m curious to know why you would like to try this? If I’m not wrong, you can just read kindle ebooks and highlights the words you don’t know. And there is a dictionary included.
The strength in LingQ is that once you have highlighted the words in yellow you can encounter them in new texts. So you can immediately focus on the words that you know you need to better pay attention to.
This definitely should be an option and it seems easy to implement. At the moment maybe you could use some sort of greasemonkey script or something similar and change the background colour to blue or yellow, so that you wouldn't notice the words?
Sorry, but that's not possible at the moment. If it helps, you can enable "Paging moves to known" under the settings and that will make all blue words known (white) automatically as you page.
Not that I know of, but you can mark lingqs as "known" as soon as you create them. This will get rid of all your yellow highlights and you'll be left with blue/white.
I do this most of the time. In my opinion, it's much easier to work with a white background behind the text than with a coloured background.