First of all I do not receive payment until you rate my work with a rating of 3 or better which I hope you will do.
In small claims as the Plaintiff you have the burden of proof by a preponderance of the evidence (more likely than not) to show that the artwork belongs to you. You can do this by showing how and when you acquired the art, how it ended up with the defendant. You can also show that all artwork on display by the defendant was on loan and that the defendant acquired your artwork in the same way. If you have witnesses that can testify your the owner you need to bring them, along with any supporting documentation. You must also show that you demanded the artwork back (in writing).
You will also need to establish the value of the artwork. In small claims you may only be awarded monetary damages. Some means of appraising the artwork should be presented as evidence. This could be bringing an art dealer , evidence of how much similar works brought etc.
Once you establish you at least owned the objects at one time the defendant will have to prove he obtained ownership not mere possession of the artwork.
After testifying to you ownership (along with your witnesses) You will need to be prepared to question the owner. You will need to ask him what basis he claims he is the owner, you can ask how he got ownership, how much he paid etc. to try yo show he never legally became the owner of the artwork, mere entitle to legal possession e.g. a loan of the artwork.
Male sure you indicate the relief you want e.g. the monetary value of the artwork, or return of the art pieces.