No peer can be a means of getting to the contents (6)
I believe the answer is:
opener
'a means of getting to the contents' is the definition.
I can't tell whether this defines the answer.
'no peer can be' is the wordplay.
'can be' indicates anagramming the letters.
'no'+'peer'='nopeer'
'nopeer' with letters rearranged gives 'OPENER'.
Can you help me to learn more?
(Other definitions for opener that I've seen before include "Batsman number one" , "Batsman; kitchen utensil" , "player, first to bat" , "batsman facing the first ball?" , "Key -- one of two batsman in a side" .)