He cites Harold McGee, who tested this theory in his book The Curious Cook: McGee weighed 252g fresh mushrooms, submerged them in water for five minutes, then removed them, blotted the surface moisture and reweighed them. The result was 258g, which, as McGee noted, is a 16th of a teaspoon of extra water per mushroom. This was after five minutes of soaking, so five to 10 seconds of rinsing under running water is going to make no difference whatsoever.
It sounds both glamorous and rustic to cook with extra-virgin olive oil, but the truth is it's not as multipurpose as it's been popularized to be. While it's fantastic for making salad dressings, marinating olives and feta cheese, or drizzling over finished dishes for a pop of fruity or earthy flavor, it's the wrong oil to be cooking with when it comes to sauteing aromatics like garlic and onions due to its low smoke point.
Being bite-sized, they can be prepared in a matter of minutes. And if you've ever gotten them at a restaurant, you probably already know blistering them is the ideal way to prepare padrón peppers. Not only is it quick, but the charring brings out more of their natural smokiness, tempers the green pepper bitterness, and adds depth through browning. And to get there, all you have to do is nothing at all.