Gigi, why PDC? Visit TTR in Cancun for the best dance parties Coco B is not good - deafening noise they call music.. In PDC I like cuban restaurant at av. 5 and calle 30, they offer free salsa class and dancing. Same goes at Zenzi beach bar, at calle 10 and the beach. also there is forum dedicated to PDC : www.playa.info/playa-del-carmen-forum/ - they might have better answer.
The Cuban place on 5th is AWESOME!!! Late night dancing to great salsa music. Can't get much better. Just a side note, if you go, wear White.