Hearing opens on findings - creating a stink as to a what a sniffer dog might benefit from (5,2,5)
I believe the answer is:
sense of smell
'to a what a sniffer dog might benefit from' is the definition.
I can't tell whether this defines the answer.
'hearing opens on findings creating a stink' is the wordplay.
I cannot really see how this works, but
'hearing' could be 'senseof' (synonyms) and 'senseof' is located in the answer.
'stink' could be 'smell' (I've seen this before) and 'smell' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'as' acts as a link.
Can you help me to learn more?
(Another definition for sense of smell that I've seen is " What the nose provides".)