Jokes aside, the programmer in me wonders why there are individual skin tone code points in the first place, instead of generic (colorless) "skin tone modifier", which would then be followed by a color codepoint from a palette of named colors, say 256 of those. So I'd write: Rightward Hand + Generic Skin Tone + Green, ZJW, Leftward Hand + Generic Skin Tone + Blue, to express a handshake between an Orion and an Andorian. Or, if 256 colors are not enough, you could write a combination of RGBA Color Modifier + eight characters in [0-9A-Fa-F] range...
This would also help with hair colors and bunch of other stuff that has separate code points at the moment. I have a feeling we'll end up with an approximation of this at some point, maybe a decade from now.