Oven has opening with leather on top (7)
I believe the answer is:
tandoor
'oven' is the definition.
(type of Asian oven)
'opening with leather on top' is the wordplay.
'opening with' becomes 'door' (I've seen this in another clue. I am not sure about the 'with' bit.).
'leather' becomes 'tan' (tan can mean to convert into leather).
'on top' is a charade indicator (letters next to each other) (in a down clue, some letters go above others).
'door' put after 'tan' is 'TANDOOR'.
'has' is the link.
(Other definitions for tandoor that I've seen before include "Clay oven" , "It has food cooked" , "Indian oven" .)