Heat the oil in a heavy skillet over medium heat. Place a few plantain slices in the oil, and cook until lightly golden in color, about 3 minutes. Drain on paper towels. Repeat with the remaining slices.
While the plantain slices are still warm, place them one at a time between two sheets of wax paper, and flatten by hand to 1/4-inch thick. Return flattened slices to the skillet, and continue fry until golden brown. Drain on paper towels, and season with salt and garlic powder.