@Onychorhynchus coronatus I have never seen them on the slide (and I would be surprised if they found a metal slide, probably hot on sunny days, very pleasant), but I have seen them on the surrounding climbing structures and ropes.
In fact I visited this place again just today and I only saw capuchins using typical climbing equipment.
I have actually seen slides in primate exhibits before in the past, but most zoos that once had them have now eliminated them in favor of more naturalistic climbing structures made from tree parts, wood, ropes, nets et cetera.
@KevinB It doesn't suprise me, they are a very arboreal species so they do prefer climbing structures.
I've seen wild capuchins climbing on swing sets and climbing structures in children's play areas in parks here in Brazil but only really because they have come to associate these with food as they get habituated to being fed by the public.