There isn't a way to see who down-voted you, as votes on posts are anonymous by design.
It is not even an information that a normal user would need to know, as there is a mechanism to auto-detect votes irregularities (both up-votes, and down-votes) and correct those votes by removing them. Moderators can see suspiciously high levels of activity between users. This means that moderators are able to detect cases of cross-voting, where you vote a user's posts, and that user votes for your posts.

In your case, there isn't anything suspicious, as you got 4 down-votes, since April 25, 2011; of those down-votes, one is the automatic down-vote given to questions closed as off-topic. You also got 10 points removed because users who up-voted your questions, and then removed their up-votes.

To add to what Clive said, leaving comments about what is wrong with the post is recommended, but down-voters are not forced to leave a comment for the simple fact voting is anonymous by design. If they were forced to leave a comment by the software, you would have a chance to guess who down-voted, except in the case there are more comments from users who didn't down-vote, but that probably happens rarely, on small Stack Exchange sites.

The general reason of a down-vote is given in the tooltip for the voting button.