Can i use Thalemine/Araport tool to find gene products that exist as homodimers (interact with their identical copy?
Yes, you can find examples of proteins which homodimerize. I am not sure if there is a single feature (protein domain, Gene Ontology term, etc) that will give you a list of all the proteins that homodimerize.
To find some examples, you may use the fuzzy search in ThaleMine and put "homodimer~" in the search box. In this case, you should see 69 genes returned and you can generate a list of these genes. Alternatively, you may select other category, such as GeneRif, and choose a publication in which specific gene(s) were shown to homodimerize.