The POST in the README is going to send the params in the request body "url form encoded" like a form in a web page. There are more samples on the doc site [1].
Regarding curl, Hurl is just adding some syntax to pass data from request to request and add assert to responses. For a one time send & forget request, curl is the way, but if you've a kind of workflow (like accessing an authentified resource) Hurl is worth a try. Hurl uses libcurl under the hood and you've an option `--curl` to get a list of curl commands.