When a question is put on hold as unclear (for example), is there a way to propose that it is reopened? Like flagging? In particular, I think this question is clear enough to be answered and I would like to post an answer:
I can think of in 4 options, which #1 and #2 are the best ones. They are:
If the question was not already edited after it was put 'on hold'; edit it for clarification (if you are positive you know how), so it can be automatically sent to the reopen queue for peer review. However, a caveat is that in many occasions only OP will be able to edit the question to address the close reason (don't edit in this case; wait for OP to step in).
Reach 3k reputation and earn cast close/reopen vote privilege, so to cast a reopen vote and send the question to the reopen queue for peer review. Leaving a comment explaining why you think the question should be reopened, might increase chances of it being reopened.
Flag it for moderator attention and explain your reasons, tell you want to post an answer; but unless it is very good reason it won't work.
Ask for help in CV Meta (kind of what you did with this post).
In my opinion #4 competes with #3. However, #1 or #2 should always be tried first, and in case of negative results, see if any new piece of information was added (e.g.: edits to question or new comments from peers), then evaluate if #3 or #4 are worthy a shot.