This probably seems like a recommendation from an obsessive clean-freak who keeps a lifetime supply of hand sanitizer on the kitchen counter, yet still insists upon handling everything with gloves. Why would you need to wash fruit or veggies if you're just going to peel off that nasty skin before you actually eat it? The problem is that when you cut away the unwashed skin and then use the same knife to cut up what's underneath, you actually may be spreading bacteria from the outside to the previously pristine inside [source: Foodsafety.gov].
To wash fruit and veggies properly, stick them under cold running tap water and rinse to remove any lingering dirt, which also reduces the amount of bacteria present. If it's a food item such as an apple or potato that has a firm surface, you can use a scrub brush. Then dry it off thoroughly [sources: USDA, Zander and Bunning].
Bagged vegetables that have been prewashed don't need to be washed again. In fact, you can contaminate the veggies further if your salad bowl or sink is not clean. If you do decide you want to wash bagged salads, wash your hands first for 20 seconds, as described on page 1. Also wash any cutting boards, dishes or salad spinners with hot water before using them for your raw vegetables [source: Foodsafety.gov].