I'm relatively new here and I want to make myself more familiarize with Islam Stack Exchange.
Who are the moderators? How and where can I give my suggestions to optimize Islam Stack Exchange?
Well, to answer your last question, you've already found the best place to give suggestions about how this site should be moderated: Meta. Active members of the community, including moderators, regularly read questions and answers here. Posts on Meta Islam inform actions on the main site.
The answer to the first question is actually more complicated than it sounds. You see, while there is a team of moderators appointed from the community, they are not actually tasked with the bulk of what would traditionally be called moderator duties. Our Theory of Moderation states:
We designed the Stack Exchange network engine to be mostly self-regulating, in that we amortize the overall moderation cost of the system across thousands of teeny-tiny slices of effort contributed by regular, everyday users.
Actions such as editing other people's posts, closing questions, flagging spam, and even deleting posts can be done without any input from the Pro Tempore moderators. Each of these actions require rather high level of reputation, which is a measure of a user's investment in the site. As people get more involved, the system learns to trust them more.
But even relatively low-reputation users have abilities to help out. Voting, for instance, helps sort answers according to quality and usefulness. Comments, used well, help authors clarify their questions and answers. Flagging helps moderators to notice problems they might not have otherwise. Finally, anyone can suggest an edit to be reviewed by others.
In short, the community self-moderates. As a user gets more involved with the site, they also get more responsibility to help keep the community running smoothly.