You can try by making the column which contains the cluster as geographic column. Select the column right click
you can create geography column based on the existing columns. then you can achieve the same.
Kind of. Better would be similar to this if it's possible -
I would like to cover the map and leave street names and etc. visible. Do you know how to do it?
I saw example just with postal codes.... Is coordinates are enough to do like that? Should I have postal codes?
I do not have any experience with Tableau Maps.
I was initially thinking that this could only be done be using MapBox or something similar to create polygons, but I think you could do this be creating a Radar Map. The information for this can be found at this link: How to create Spider or Radar chart in tableau.