Bean producer finally hires Spanish painter who's no good (4)
I believe the answer is:
soya
'bean' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for soya that I've seen before include "Plant seed, meat substitute" , "Protein-rich vegetable" , "Bean used in dark sauce" , "Form of protein derived from beans" , "nutritious bean" .)