What is the difference between Italians and Sicilians? Is there any difference at all?

Nationally, no difference. Sicilians are still italian citizens and members of the E.U. Ethnically, yes. They derive from clans from Malta and Turkey. They are where 90% of mafia comes from. They are masters of deception and corruption. They are considered the 'blacks of Italy' by continental Italians due to their more olive toned skin and sub-culture.