Add a calculated value to your repeating section. In that calculated value you will 'build' your xpath query. This will be a concatenation of the static component of the url ie. 'http://site/list/form.aspx?UID=' and then some local value. IF you were to
do the logical thing and just pick the field from the prompt it'll just show you the same value on all items.
Instead you have to cheat, in the formula section you should tick the box that says 'show xpath', then replace the long section for the local field with something like 'current()/d:Title' which will get the current item's title value.
That will then display your link location and you can copy the xPath that it uses into a link's data field so that the link automatically gets the right path.
This shouldn't work in browser forms according to some documentation however it does in practice. There's probably a couple of blogs that describe this better than I have done but it's possible to do