All along Atlantic Avenue in Delray Beach, you'll find some terrific restaurants without the kind of crowds that are common on South Beach or Las Olas.
One of my favorite spots is Cabana, which features a nice Spanish menu and an beautiful bar area. As with most of the restaurants along Atlantic, the atmosphere is casual, and there is both indoor and outdoor seating. There are many shops along Atlantic as well, so sitting outside provides a good opportunity for people watching.
Cabana makes a nice mojito (try the unique berry mojito for a different spin on the traditional mint flavor).