openssl: How to configure private key size for secp256k1

I am trying to understand if it’s possible to configure a private key size for the given curve.

openssl ecparam -name secp256k1 -genkey  -----BEGIN EC PARAMETERS----- BgUrgQQACg== -----END EC PARAMETERS----- -----BEGIN EC PRIVATE KEY----- MHQCAQEEIMda3jdFuTnGd2Y9s9lZiQJXKSpxBp6WQWcurn4FnYogoAcGBSuBBAAK oUQDQgAEI272v3lIoVkLZEbsJ/1l6Wfqbk8ZeybzzhtUN60EOhCRsR8rOLAIbbDl ncOT1vtzEj5NZxQEYdopFMb10CfccQ 

Was trying to read openssl documentation to see how to configure the length of the private key but failed to find anything regarding it. Could you advise?