Please remember that food here in the Yucatan is not like TexMex, and also Yucatan cooking is different than some other parts of Mexico. That said, you shoud try Casa Denis, just off the Zocolo. This family has had this traditional place for many years, in fact I believe it was the first on the Island. It is loved by both locals and tourists alike. Good food and reasonable prices.
When walking on the waterfront turn into the Zocolo at "PAMAS" department store. Walk to the end of the square and about another 150 feet on your right. enjoy our island!!!