"In-order to walk among us, they disguise their apearence by cloning human flesh over their own reptillian skin"
Cloned Human Flesh is a technology achieved by the Visitors.
Purpose & how it works?Edit
The purpose for the cloned human flesh is because so it hides the real truth of what the Visitors really look like, so they wouldn't seem distant to the humans and can sneak into every facet of human society.
How it works?EditHuman skin is applied to the V flesh, and neural connectors from the skin are connected to the V brain which therefore makes the V not probably notice it's got a reptile flesh with human flesh on top of it. It may only notice the human flesh.
Since the V's have been on Earth a long time, it's likely that the first time they arrived they took DNA samples from abducted humans and used them to replicate human skin.
It is possibly responsible for Visitors being susceptible to human emotion. That the curse of wearing human skin enables the V to feel. Thus the reptillian flesh cannot feel. However, it is only one of many other theories, pertaining to why are the Visitors susceptible to human emotion.
Flaw (e.g. human emotion)Edit
According to Anna, every V can be infected by the human skin. The probable theories are that V skin cannot feel anything and so cannot feel any emotion, but with human skin they can feel things and so experience human emotion.
Anna finds human emotion a threat to the existence of the Visitors, and finds efficiency a more priority that one owns feelings. And will try and exclude and remove anything who shows these traits in season 1, but in season 2 since she is showing human emotion, it is probable that she may not resort to measures like that.
Skinning is a punishment which is meant the removal of the human skin and maybe the V skin, however it's not known.If the human skin is removed painfully, the person wearing it would feel excrutiating pain but it was not known at first that it would kill that person. However, Ryan confirmed in the episode Laid Bare that a V can only survive 30 minutes after having it's human skin removed. Skinning was either introduced when cloning human flesh was discovered, or it's been in their society for a long time and it's actually to remove the V skin.