I'm rather new to this community, like the title says, I'd like to know what's the difference between a "community wiki" question and a normal one.
And, is there a place where I can access all "community wiki" questions?
Community Wiki (CW) posts are owned by the community. The main difference to normal posts is that:
You can get a list of CW questions by using the search operator
Now, there's a difference between CW questions and answers. While you can choose for any answer of yours to become a CW post (just click the checkmark), questions usually don't become CW, unless a moderator makes them CW, or they accumulate more than 15 answers. When a question becomes CW, all answers become CW as well.
We don't really create CW questions anymore. Back in the past, making a question CW was used for "fun" questions or posts that'd otherwise be considered not constructive. A few years ago that changed:
Community wiki should never be used as a get out of jail free pass for joke and fun questions
(Although some sites still like to do it.)
In any case I'd encourage you to read the blog post mentioned above as well as the Meta Stack Overflow FAQ about CW.