From the server's web UI, you can select a recording's View Details option (in the same place as the Redetect Commercials option). Alternatively, to get a listing of all your recordings (including their fileIDs), you can GET /dvr/files
.
(Those are the API endpoints and required operation. Pair that with whichever tool you prefer. For instance, if I wanted to get a list of all my recordings, I personally would use (assuming my DVR server is at 10.0.10.81):
curl -XGET http://10.0.10.81:8089/dvr/files > files.json
And then if the file wanted to scan for commercials has the fileID of 6209, I would use:
curl -XPUT http://10.0.10.81:8089/dvr/files/6209/recomskip
And if you mean "not on the same local network" by "remote", then you need to SSH in to some device on your local network, as I don't believe the DVR server accepts API requests from public IPs.)