Cut: Slice the sweet potatoes into about ¼-inch thick slices or potato-fries-sized sticks.
Salt: 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.
Fry: 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.
Serving: Serve as a side dish with parrilladas (bbq), or as an appetizer with a dip.