Mix water and salt. Soak the cassava or sweet potatoes in 4 cups of salted water for half an hour. Remove the cassava or sweet potatoes from the water.Discard the water. Pat cassava or sweet potatoes dry with a paper towel.
Heat the oil over medium fire. Fry cassava or sweet potatoes until light golden (be careful with splatters). Rest on a paper towel to absorb excess oil.