The best advice yet is "go with the flow." Don't rush anything, smile at strangers (they might end up as firm friends) and use the bits of Arillas that appeal. The beach is gorgeous, the sea is shallow and often warm. It depends on weather conditions and time of year. I prefer late October, when apart from being wet, you wouldn't know you were in water.
About food, I so identify with
treat every evening as an adventure and try which ever takes your fancy
That's what we did in 2002/3 and still do in 2014. There are 11 major places to eat along the seafront, let alone if you venture 200m inland where there are many more, some regarded as the best on Corfu. Arillas is small compared to many resorts, but it offers more than many much bigger places do. And a warm, village atmosphere you will not find anywhere else at all.
Phil