OpenSSL's rsautl allows signing with a private key. This is without a hash. Then recovering the signed file with a public key.
I've looked at CryptCreateHash/CryptSignHash/CryptHashData but I'm not sure how to do it. I believe those functions will only sign the hash of the data, not the data itself.
Is there any way I can sign with the private key and no hash involved?
Edit: Made necessary changes from jww's recommendations.