I suppose there are several ways…I would place a layer or two in a flat, glassware-type wash tub or something similar that can hold the fingerlings intact but still allows for easy draining. These should easily handle 10-20 lbs. per tub. Then I would give them a good warm water rinsing with a medium-pressure nozzle, gently moving around with your free hand to ensure everything gets a good rinse; then allow the tray to drip-dry until needed for further prep.

For smaller amounts, such as fixing for home entertainment, you could use a salad spinner. Wash the potatoes in the perforated insert provided and drain into the sink. Then place the insert into the spinner, put the top on and crank just enough for the excess water to leave the insert basket.

For foodservice, you can use this same method with some of the brands that make commercial salad spinners. Search for a five gallon salad spinner on the internet for several examples.