How to use fn:starts-with() and fn:ends-with() with cts:uris()

You could use cts:value-match() with leading and trailing wildcards to find all of the values that start-with and end-with the value.

Then use cts:path-range-query() with those values in a call to cts:uris()

let $path := "/doc/foo";
let $word := "bar";
(: find the values that start with and end with the $word :)
let $values-starts-and-ends-with := (
  cts:value-match(cts:path-reference($path), $word||"*"), 
  cts:value-match(cts:path-reference($path), "*"||$word)
) 
(: use those values to find the URIs of docs with those values at that path :)
cts:uris("", (), cts:path-range-query($path, "=", $values-starts-and-ends-with))