Has a World Cup game ever ended 22-0?
Exactly once. On April 9, 2001, Australia beat Tonga 22-0, and no World Cup game before or since has ended that way. When it happened it was a scorigami, the first 22-0 in league history.
That makes 22-0 the 43rd most common final score out of 53 that have ever occurred in World Cup. One point away, 23-0 has happened never and 22-1 has happened never.