The fingerprint referred to on SSL certificates is basically an integrity check. Just like humans have unique fingerprints, each security certificate has a unique fingerprint. This is basically a hash of the certificate. So, each certificate has a unique fingerprint or hash. The hash can show if a certificate has been forged or modified.
Fingerprint readers are considered biometric means of authentication. There might be some services out there that would use biometric authentication but they are not very prevalent at this time.