It is indeed a fabulous restaurant - my favourite on the island, in fact.
It's pretty easy to find. If you head to Dalt Vila in Ibiza Town, and walk up the ramp to the big arch in the wall (by where the Croissant Show is) and turn right you'll see loads of pavement restaurants and it's on the right-hand side a bit further up beside the Oliva Restaurant. If you've got a map, the actual street it's on is Placa de Vila.