Expert beneath waves that break skin (7)
I believe the answer is:
surface
'break skin' is the definition.
'surface' can be an answer for 'skin' (I've seen this before). I am unsure of the 'break' bit.
'expert beneath waves' is the wordplay.
'expert' becomes 'ace' (ace is a kind of expert).
'beneath' says to put letters next to each other (in a down clue).
'waves' becomes 'surf' (I've seen this before).
'ace' put after 'surf' is 'SURFACE'.
'that' acts as a link.
Can you help me to learn more?
(Other definitions for surface that I've seen before include "In water, come to the top" , "Top side" , "Outside part" , "Uppermost layer" , "Facade" .)