Go to: http://www.seg-social.es/Internet_1/index.htm and follow the instructions in the video below. If the reply comes back negative, check how to make an application here and here
How To Check Spanish Health Care Entitlement On Line
We can help you if you don't Speak Spanish and need help in Tenerife with any sort of paperwork, Translations, NIE, Certificate of Residence Registration, Tax returns etc. etc. etc.