If you can't figure the making skintones out (like me, lol), you can always make a new town and make all of the people in the houses have green skin.
There still will be regular skinned maids and stuff like that, but you could always install Twallan's MasterController and you can change their skintone to green
This mod adds a menu called "NRaas \ Master Controller" to the following items in town:
1) Every Sim
2) Every Computer
3) Every Lot
4) City Hall
Whenever you see a sim, any sim, click on it, go through the NRaas > Master Control > Advanced > CAS edit. Do this the first time you meet a new sim, and eventually all your sims will look the way you want. This author seems to be very professional and he updates his mods very often. This command works on every single sim as long as you can click on them, this includes the pizza guy, the repoman, mailman, maid, etc...