Unless authentically Organic, I think it's wise to assume that every fruit and vegetable has been exposed to some type of pesticide (and 'organics' may have been contaminated by any number of human-transmitted pathogens. Singling out citrus peel as risky doesn't make sense to me. I wash, in mild detergent, and thoroughly rinse just about every fruit and vegetable that we use -- even those with peels that are discarded and not eaten. I understand that the pesticides used on tropical fruits such as bananas are so potent that transfer from hand to fruit is inadvisable. If we were to avoid eating skins that have been exposed to pesticides then we would not be eating sugar snap peas, snow peas, strawberries, asparagus, tomatoes, baked potatoes, etc, etc, etc. IMHO, it's wise to be cautious but not paranoid.