Mash garlic to a paste in a mortar with some salt. Grate the plantains on the medium holes of a grater; when all are grated, mix well with garlic. Heat oil on medium-high until hot, then with a spoon grab some of the shredded plantain mixture, press slightly and slide into the hot oil. Crisp fry until golden brown on each side; carefully turn with a fork or other implement. Put them to drain on a plate with paper towels or paper bags and sprinkle lightly with salt.