Spain you once granted a small opening (6)
I believe the answer is:
eyelet
'a small opening' is the definition.
(I've seen this before)
'spain you once granted' is the wordplay.
'spain' becomes 'e' (abbreviation for Espana).
'you once' becomes 'ye' (I've seen this in other clues).
'granted' becomes 'let' (both can mean allowed).
'e'+'ye'+'let'='EYELET'
(Other definitions for eyelet that I've seen before include "It is tiny place" , "Small hole through which a cord is passed" , "Small hole through which lace passes" , "Small opening for needle or shoelace" , "hole in shoe leather?" .)