Yes, you can use Universal SSL if you signed up through a partner. As of December 9, 2016 all new domains added to Cloudflare via partners have Free SSL enabled.
Please note that if your domain was added before Universal SSL was enabled you will need to delete and re-add your domain again in order for SSL to be provisioned automatically.
Additionally, if your domain was added using Cloudflare Partial (CNAME) set up, you must always have CNAME verification records in place to verify the domain, you can use this Cloudflare API call to obtain SSL verification CNAME records to trigger the certificate to be issued (instructions).
You can check the status of the SSL certificate on the Crypto tab in the Cloudflare dashboard. Additional information can be found in our SSL FAQ.