Try Mary's Coctaleria on the Malecon, on the right, about 2 places in from Con Flavio, just next to the little statue. The fish soup in foil is excellent and the large seafood platter is enough to serve 4 easily. 3 or 4 kinds of shrimp, salad and fish. If there are two of you you have enough for tomorrow's lunch as well. Buy fresh shrimp at Mary from Cisco too !!
The Blue Marlin, on one of the short exit streets out of the the Malecon is pretty good. No ocean view but you can dine in or out.
For atmosphere I love La Palapa in the Malecon, but the food has been horrid. Flies in the wine, etc. Dont bother with The POint either. An incredible location but marginal food.
Playa Bonita has a very nice restaurant, right on the beach, with a buffett Sat Evening about 6. and I think a breakfast buffett on Sunday. They have an Oldies DJ that is popular, although it was a little loud for me, but people were dancing and they had a good crowd on Friday about 1 week ago. I had the Octopus off the menu and it was excellent.
La Cuerva is popular, and the food is good, the people are nice, but you could be eating in a barn in Tucson for all the atmosphere the place has.
On a slightly different note, if you are up for some late evening entertainment on Wednesdays, go to the Crow's Nest, upstairs from the Lighthouse restaurant up on the top of whale hill. Starting at 10 or so, a group of mixed jazz musicians gather for a jam session. They are good !!