From *what I can see, there is something that allows a user to single handedly close that topics questions.
So is there something similar for someone who has asked the most questions on that tag?
Gold tag badges (or indeed all tag badges) only take into account answers, not questions. There aren’t any closing powers that users can acquire (at the moment) from asking a great number of questions in a certain tag, even if those questions receive lots of upvotes.
Of course, asking lots of questions does give one more generic privileges on the site, through reputation—but nothing tag-based.
There’s a good reason for this: the gold tag badge powers are not merely a reward for answering a bunch of questions, but are given to people who understand a topic well enough to know when questions are duplicates. Giving lots of well-received answers is a better metric of that than asking lots of well-received questions. After all, many well-received questions are asked by people without much knowledge of the topic at all: they’re just good questions. Indeed, asking a large number of questions in an area might, on average, indicate a great deal of curiosity about the area but not in-depth knowledge (though, if this does hold, it is certainly not true in all cases). Further, the badge is also a sign that you’ve seen a lot of posts that might be duplicates.
You can get a number of excellent gold badges for asking questions (though again, nothing tag-based).
For asking a lot of questions about a topic, there isn't a specific award. However, there is an easy way to find out who has asked high reputation questions about a tag. On a tag page, eg. harry-potter, follow the "top users" link to go to a page like this.That page contains a list under the heading "Top harry-potter Askers: All Time" which shows that Slytherincess has asked questions in this tag for a total score of 3891 (score means the difference of upvotes and downvotes on a post). The list is sorted by the total score, not the number of posts.
Update. For reference, here are the users who have posted the highest number of questions in each tag.
This is based on the data dump from 2016-09, so it's not completely up to date. It counts all questions, including tag wiki ones and closed ones, but not deleted questions, and it doesn't care about the score. The number of questions in that tag is shown before each user. Only users who have asked 24 or more questions are shown, and only for tags with 100 or more questions.