Ticks off a number of skins (6)
I believe the answer is:
chides
'ticks off' is the definition.
Although both the answer and definition are verbs in their -s form, I can't see how they can define each other.
'a number of skins' is the wordplay.
'a number of' becomes 'c' (I can't justify this - if you can you should give a lot more credence to this answer).
'skins' becomes 'hides' (hide is a kind of skin).
'c'+'hides'='CHIDES'
Can you help me to learn more?
(Other definitions for chides that I've seen before include "Admonishes, rebukes" , "Censures severely or angrily" , "Scolds, rebukes" , "Admonishes, reproves" , "Admonishes, scolds" .)