To peel the plantains, cut off both ends of the fruit. Then, use the tip of your knife to slice end to end along one of the ridges of the peel, being careful not to cut into the fruit. Remove the peel from the fruit and discard. Once peeled, slice the plantains crossways into 1 inch pieces.
In a cast iron or heavy bottomed pan, heat 1/8” of oil to 365F over medium-high heat. Fry the plantains flat side down, about 2 minutes per side, until lightly golden. Transfer the plantains to paper towels and allow to cool slightly. Keep the oil hot.
Use the plantain press or large can to smoosh each piece of plantain (on the flat side) into a disk. Do not try to get them too thin or they will break apart.
Return the plantains to the 365F oil in batches, and fry about 2 more minutes each side. Drain on paper towels, season with salt, and enjoy hot with cilantro-garlic dipping sauce. Tostones are best eaten right away.