Is it possible to have a zero skew in the design?

Answer:

Theoretically it is possible....!

Practically it is impossible....!!

Practically we cant reduce any delay to zero.... delay will exist... hence we try to make skew "equal" (or same) rather than "zero"......now with this optimization all flops get the clock edge with same delay relative to each other.... so virtually we can say they are having "zero skew " or skew is "balanced".