How to wash pesticides from fruit skins?
A long term answer would be to grow your own if possible. That way you have complete control over your food. Or at least purchase from a local farmer that is willing to let you see how he/she grows their produce. 

Even organics need to be washed. Most all commercial organics use a form of pest control (most likely diatomaceous earth), they also use natural fertilizers like manure and compost. None of those things are items you need to directly ingest.

The best advice I have is to wash then soak fruits and vegetables in lukewarm water. After a soak wash again. For foods with pitted surfaces, strawberries, potatoes, etc, use a soft bristled brush to gently scrub the food. That will get most anything off the outside.

Of course there will be trace amounts of anything that was sprayed on the item inside of the item.

Hope this helps.