*Note: The secret to great latkes is said to be starchy potatoes like Yukon Golds.
Preheat oven to 250°. Peel potatoes and coarsely grate by hand, transferring to a large bowl of cold water as grated. Soak potatoes 1 to 2 minutes after last batch is added to the water, then drain well in a colander.
Spread grated potatoes and onion on a kitchen towel and roll up jelly-roll style. Twist towel slightly to wring out as much liquid as possible. Transfer potato mixture to a bowl and stir in eggs and salt.
Heat ¼ cup oil in a 12-inch nonstick skillet over moderately high heat until hot but not smoking. Working in batches of 4 latkes, spoon 2 tablespoons potato mixture into skillet, spreading into 3-inch rounds with a fork. Reduce heat to moderate and cook until undersides are browned, about 5 minutes.
Transfer to paper towels to drain, and season with salt. Add more oil to the skillet if needed. Keep cooked latkes warm on a wire rack set in a shallow baking pan in the oven.
Serve with sides of sour cream and applesauce.