<p>Being a Windows developer I'm currently working on my own project using LAMP. I understand what I need to know of PHP and MySQL, but Linux looks huge and it's not clear where to start and what is enough given my goals.
And my goals are to grasp general concepts, being able to deploy the project to a hosting provider and to be able to monitor the site's performance in order to spot problems, load issues, etc.</p>
<p>I know, the best solution is to get a Linux administrator to do that, but before I can do that I need to do it myself.</p>

You might consider, based on your introduction, a
WAMP
option (Windows Apache MySQL Python, Perl, and PHP).
Learning Linux isn't
hard
, but it's certainly not a short task, either. There're a lot of system administration tasks that carry over platform-to-platform, but the real answer to your question is to become at least a hobbyist Linux administrator, and then go from there.