1In deep 12-inch skillet or deep fryer, heat oil to 375°F over medium-high heat. Slice plantain into 1/2-inch pieces. With tongs, carefully place sliced plantains in hot oil. Cook 1 to 1 1/2 minutes, turning frequently. (Cook ripe plantains 45 seconds to 1 minute.)
2Remove from hot oil, and place on paper towels. Using tostonera or the bottom of glass, press each plantain slice to about 1/8-inch thickness. (Press ripe plantains to 1/4-inch thickness.)
3Return pressed plantains to hot oil. Cook a few at a time, turning frequently, until golden yellow and crispy. Drain on paper towels. Sprinkle evenly with salt.