As the rule amongst Spaniards is not to swim for a couple of hours after eating for fear of a "corte de digestion", you could do what I do and go for a hike up one of the Perdiguera's small mountains.

Satellite image of Perdiguera showing the restaurants

Sat map of Tabarca (the juxtaposed Google street map doesn't match and floats a few kms North over the empty sea) Tabarca is excellent for Scuba diving BTW - I'm guessing this photo was taken out of season.