Tucking into what's left, something for sticking peas? (7)
I believe the answer is:
legumes
'peas?' is the definition.
(pea is a kind of legume)
'tucking into what's left something for sticking' is the wordplay.
I cannot quite see how this works, but
'left' could be 'leg' (left leg) and 'leg' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for legumes that I've seen before include "Peas, beans, and lentils" , "Plants that bear their seeds in pods" , "Pulse" .)