By Veronika Bondarenko After more than a year at the helm of the wing chain, Charlie Morrison resigned unexpectedly. Pizza and salads are opposites. One stands as the standard-bearer for healthy food, while the other carries the flag for indulgence. Leaving a pizza chain to lead a salad chain seems like a huge leap in the opposite direction, but that’s exactly what one CEO is doing. After 10 years of leading Wingstop (WING) – Get Wingstop, Inc. Report and guiding it through an IPO, chairman and chief executive Charlie Morrison unexpectedly announced his resignation on Monday. “It is with mixed…