It all really depends on what kind of photography you want to do. The good news is both lenses are the XF line, so you get the better quality in the Fuji line. (vs XC lenses)
Obviously, the 16mm is a prime, so you are 'stuck' with 16mm (24mm full frame equiv). This is rather wide, and likely great for landscapes, but limited for portrait, sports, etc. The 18-55mm gives you more options (27-85mm full frame equiv) for landscape, portrait, etc.
The 16mm is a very bright lens, with much wider aperture of 1.4, vs the 18-55 which has a f/2.8 to f/4 on the zoom range. Typical of these higher end lenses, these apertures are are still rather bright, but not 1.4. I do not have any data, but typically prime lenses are more sharp than are zoom lenses, and I would expect the same here with the 16mm vs the 18-55.
Finally, the zoom offers OIS that stabilizes the lens, and can give you better results from slower shutter speeds. This likely brings the lens down to similar places the 16mm can go (in terms of available light) with its f/1.4.
All things considered, I would go with the 18-55, as it gives you more options for more kinds of photography. With it, you can determine if you need the wider, brighter lens for your photography, selling the zoom or adding the 16mm to your lens collection later.