Having said the above, if you teach a specialized subject like art, music or swimming, you can negotiate for more money and probably get it.
The key point I want to make is you will be getting a gazillion dollars more than your contemporaries in that society and as a westerner you will be expected to share the wealth. It is sort of an odd phenomenon I find that the indigenous population feels almost "entitled" to ask you for money and almost demand you to give it to them.
In regard to this picture on the right, you will be harassed more than the rest of the population when you go to tourist sites, especially if you get off of a tourist bus, for example. You are fair game and I accept that. Give or not as you like but I assure you if you do not give it will not be pleasant.
What I personally do not like is the service people that you deal with on a continual basis such as a barber or cleaning person who gets to know you on a personal level. Although Asians are shy people as a group, once a few individual persons feel comfortable with you they will feel no hesitation to ask you for money because someone in their family is injured or they were sick this week and short of money and so on. It is just an expectation that you will give them the $100 they need because you are 'western.' This is the sort of situation I find most uncomfortable on a personal level. When you give them the money the first few times it never stops. I guess, in essence, I do not like the feeling that I am just expected to share my "wealth" no matter how limited it may be.
I remember one time in Myanmar, where banking is very difficult, asking a colleague how I could send money to my son in Canada. He looked at me really quizzically for a few long seconds and I thought he was thinking about the mechanics of how to send or wire money, Instead he asked me to repeat the question about sending money to my son. Why would you send money to your son, he asked? It was such a foreign concept to an Asian since it is just the other way around in Asia. A child will always send money and support to his or her parents, no matter how rich or poor the parents are. If the parents are rich they will find a way to give the money back to their children in presents or other things, but the money always goes ONE way and never the other.
Asians, once you become friends, will just see you as extended family. If you are comfortable with this situation there is absolutely no problem. You will help them to the extent of your ability and everything will be fine. If you are not all right with this, you will have to stay a bit aloof in your relationships or learn how to say no and then live with yourself afterward! It is tricky line to walk and you will figure out your own answers.