If you're going to file a Petition for Expungement, you would want to file it with the court that convicted you, and that court can either deny it, grant it, or schedule a hearing on it to talk to you face to face. Assuming you do get a hearing on it, you're going to want to come in with more than "I haven't committed any new crimes;" you'd need to show a court that you've actually done lots of positive things since the case, and I mean every detail of every positive thing.
That being said, if what you're saying is true and you were actually convicted of a civil forfeiture, it's not your criminal record, because if that's the only thing you've done, you don't actually HAVE a criminal record. A civil forfeiture like this is at the same level of a speeding ticket. Now, granted, employers don't have to hire you for speeding tickets either, but my point is that they don't tend to check municipal violations in background checks; they tend to focus on misdemeanors and felonies. So your petition for expungement may be denied purely because there's no crime to expunge.
First, the fact that you were "convicted" of a civil non-criminal theft will probably NOT prevent you from pursuing expungment under Sec. 973.015 Wis. Stats. A fairly recent Court of Appeals decision ruled that the expungment statute DOES apply to non-criminal ordinance violations. Because that Court of Appeals decision was NOT published, a trial court can but does not have to follow the ruling. Therefore, I do agree with one aspect of Attorney Goldman's answer, if you follow through, you will need to come armed with more than just "I haven't committed any new crimes".
The bigger problem you might have is the requirement of Sec., 973.015 that the sentencing court make a determination on the expungment issue AT THE TIME OF SENTENCING. I practice in counties all over the state and have found that more and more trial judges are strictly applying this lnaguage AGAINST defendants. At the original sentencing hearing, did you, your attorney, the DA or the court mention expungment? If yes, you should be able to bring your expungment petition. If no one mentioned expungment, and the trial judge wants to be "difficult", the court could deny your motion on this ground alone.
My advice to you is to get a lawyer who is familiar with your sentencing judge and the DA that prosecuted the matter. The old saying "Its not what you know but who you know (and how well you get along with the important people)" might be especially true for your case.
While I generally agree with Attorney Golden's answer, I would add civil ordinance violations may be expunged. (See the Melody P.M. case: http://www.wisbar.org/res/capp/2010/2009ap002994.htm.)
Expunging civil ordinance violations, however, involves complex legal arguments, requiring an attorney. Such an undertaking is likely to be expensive with no guarantee of success. You should weigh this against the fact a civil ordinance violation is not a crime.
As for your second question, you may answer "no" based on the information contained in your post.