If you are going to import questions via CSV you can set the ‘tags’ field for each question. Then go to Admin > Stats and click the ‘Reindex content’ button, your tag pages should be filled.
There was also an importer plugin posted here a little while back which may be of use. I think it handled all the indexing and such for you.
In your theme (or layer plugin), in the head_script() function add this at the bottom:
$this->output_raw("<script>var qa_tags_complete = 'question,example,tags';</script>");
And replace question,example,tags with a comma-separated list of whatever tags you want to show up. Or you can add to existing tags by using += instead of =
You could try the above in conjunction with my Tagging Tools plugin if you want to force the user to use those tags.