Put on openers -- absurdly easy, pinching runs for ages (7,5)
I believe the answer is:
donkeys years
'ages' is the definition.
(expression meaning a very long time)
'put on openers absurdly easy pinching runs' is the wordplay.
'put on openers' becomes 'donkeys' (I can't justify this - if you can you should give a lot more credence to this answer).
'absurdly' indicates an anagram (I've seen this in other clues).
'pinching' is an insertion indicator (taking inside).
'runs' becomes 'r' (cricket abbreviation).
'easy' anagrammed gives 'yeas'.
'yeas' placed around 'r' is 'years'.
'donkeys'+'years'='DONKEYS YEARS'
'for' is the link.
Can you help me to learn more?
(Other definitions for donkeys years that I've seen before include "An age" , "Ages" , "forever" , "What's evident in old ass" , "A long time (spent on Blackpool beach?)" .)