Cut both ends of the plantain.
With the tip of a sharp knife, cut through the skin, lengthwise, just deep enough to go through the skin (don’t cut through the flesh).
With your fingers, separate the skin from the flesh.
Note: Green plantains have a tough skin and sap, however, once you make a cut through the ridges of the skin, separating the skin from the flesh should be easy. Discard the skin.
How To Cut Plantains: For tostones, slice the plantain into 2-inch chunks, diagonally.
In a large, deep, heavy bottomed pan, heat the oil over medium heat (If using a deep-fryer thermometer, the oil should register around 300F -325ºF)
Cooking in batches, add about a third of the peeled and cut plantain slices into the skillet and cook, for about 3-4 minutes per side, or until golden but slightly pale.
Transfer to a cooling rack or plate lined with paper towels, to drain. Continue frying the remaining slices.
If you have a plantain press (tostonera) or a tortilla press, line it with plastic wrap, otherwise line your cutting board with a large piece of plastic wrap.
Using your plantain press OR with the bottom of a drinking glass or a small plate, flatten the fried plantains by smashing them to about ¼ to ⅛ inch thick. Smash gently to prevent the slices from breaking. The edges will crack but the slices should be kept in one piece.
Before frying the plantains for a second time, make sure to heat up the oil to medium-high heat (about 350ºF to 375ºF).
Add the smashed plantains back into the oil and fry them for about 2 additional minutes per side or until golden brown and crispy
Remove from the oil and transfer them to a paper towel lined cooling rack or plate. Immediately season with salt. Serve with Cuban mojo, ketchup mayo or guacamole.