For 1 night-
KM5 has to be a top shout. great restaurant and pre club.
If you want to hang out nearer Ibiza town, one of the best restaurants is Sa Punta in the nearby bay of Talamanca great food and one of the best views on the island.
If you are staying in or near Santa Eulalia there’s loads of options, it’s where we always stay for that very reason. That said I would recommend Ses Savines as certainly one if the best restaurants.
Oh and there’s always Atzaro, pricey but awesome, utterly awesome.
(plus there’s always Oliver at Ibizamtb.com if you have time for a ride – top bloke as well)
I could go on but I’m going to stop there …. For the time being :)