Spread potatoes and onion on clean dish towel; roll up, twisting towel to extract excess moisture from vegetables.
In bowl, whisk eggs, flour, 1/2 t salt and 1/4 t pepper until smooth
In large nonstick skillet, heat 1/4 cup oil over medium-high heat. Ad vegetables to batter; mix. Spoon mixture into skillet, allowing heaping 1 T for each fritter; with back of spoon, flatten slightly. Fry, six fritters at a time, 4 minutes. Turn; cook 2 to 4 minutes. Drain on paper towels; keep warm while frying remaining fritters, adding more oil if necessary.