Yes, indeed, “Dust in the wind” is one of Kansas most popular songs :) I love such song ;)
The sentence “All we are is dust in the wind” is perfectly correct, BUT your confusion may come from the fact that the floating quantifier “ALL” is being used, and it may occur/appear in more than one position in a sentence.
If you read it like this, you should be able to see it better:
“Dust in the wind is (all) we are”
“We are (all) dust in the wind”
“We (all) are dust in the wind”
WE ARE DUST