These are fabulous! Look 100% better on than in the photos (and they look pretty appealing in the photos).
They're a cropped trouser/ culotte... sitting at 'midi' length.
They're an XS but for once Zara is coming up small and I'd say they are a good fit for a UK8 - small UK10.
They have a side zip... the front tie is a detail.
The fabric label has been cut out but I'd say they are a cotton/ polyester mix of sorts.
In excellent condition apart from a super tiny mark in the front, which is obscured by the tie. Please see final photograph.