This reddit thread shows how to accomplish this through the normal API: http://www.reddit.com/r/redditdev/comments/1si9m0/fetching_comments_by_id/
Here's the code to do this with PRAW:
import praw
r = praw.Reddit(user_agent="bot by /u/{0}".format("YOUR-USERNAME"))
submission = r.get_info(thing_id="t1_asdasd")
print(submission)