I recommend Escondido in Sandgate, always, although Tinto Tapas in Sandgate is also good (this is based more on friends recommendations as I've only been there once). The Hermitage sounds like it might be just about right though, in terms of ambience and specials.
This is part of my site The FG that I built in a fury of excitement when I first came to Folkestone in approximately '04. I had been a frequent visitor for a while before that but I am technically one of those Down From Londons you get now. This site was updated more frequently with a calendar of events + voting for best venues + things, and I know it was a handy resource for those who were thinking of moving to the area. Now I've moved out of Folkestone again (though only to Hythe) it doesn't get as much love as it used to. Ironic really as The town is now becoming the exciting place we always thought it was about to become. My name is not Gerald by the way, this comes from a pretend newspaper in an episode of Brasseye or something, the Portsmouth Gerald, and how there is a local paper here called the Folkestone Herald. Puns like this are GRATE aren't they? Do get in touch if you have something to contribute, email anythign @ this domain, or try @folkestone or @pauly on the twitter.