That is very interesting. In open data, downloads are done from cache so if you want to create a URL of filter to download filtered data you will have to have cache URL I guess? I don't know. To simplify, I don't see any way to create a download URL for filtered dataset in open data. However you may able to create some download URL from REST end URL of your dataset hosted in ArcGIS Online or ArcGIS Server if you are comfortable with that.
Sorry, not much of a help!