The Sentinel tile files is so big that it was not easy to put it on a web site in a quick viewer. But my colleague from CESBIO, Michel Le Page found a way, through a geoserver instance we have in the laboratory. So if you want to find quickly which tile name corresponds to your region of interest :
http://www.cesbio.ups-tlse.fr/multitemp/?page_id=9683
For some reason, the first view shows the tiles and OSM in different geometries, but everything converges when you zoom in. We still need to improve our openlayers skills. Hope it is useful for you !