It seems to me that you don't need to wash vegetables you're going to peel. If toxins are on the surface, peeling solves the problem; if toxins have been absorbed into the flesh of the vegetable, washing won't help.
Is that right, or am I missing something?
First, I always rinse produce well with tap water even before putting it into the refer. I grew up on a farm and witnessed what it may be exposed to even when the farm hands care. I would also wash anything that is being peeled as the peeling process requires--at least for me--my fingers to touch the peeling, and then the peeled veggie as I am peeling the rest of it.
The reason to wash is cross contamination.
You are going to handle both the peeled and unpeeled.
The utensil (knife or peeler) will come in contact with both unpeeled and peeled.
A banana where you don't touch the peeled could be an exception. I sure there are other cases where you don't come in contact with the peeled.
Wash nuts would be a problem as they would get soft. I don't wash nuts.
Another reason to wash is to get rid of grit.
If you are to cut and only eat the inside (e.g. watermelon) you should should also wash for cross contamination.
