See red perhaps more than once, beginning to struggle with tension inside (7)
I believe the answer is:
witness
'see red' is the definition.
'witness' can be an answer for 'see' (to witness something is to see it happen). I am not sure about the 'red' bit.
'more than once beginning to struggle with tension inside' is the wordplay.
'more than once' becomes 'wines' (I can't justify this - if you can you should give a lot more credence to this answer).
'beginning to' suggests taking the first letters.
'with' says to put letters next to each other.
'tension' becomes 't' (abbreviation for surface tension).
'inside' indicates putting letters inside.
The first letter of 'struggle' is 's'.
'wines'+'s'='winess'
'winess' placed around 't' is 'WITNESS'.
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for witness that I've seen before include "Evidence, proof" , "Court testifier" , "Onlooker" , "Observer" , "Attest" .)