Start by cutting off the ends of the plantain. Then, using the sharp edge of the knife, run the knife along the edge of the green peel to create a lengthwise slit the way down. Using the edge of the knife or your thumb, start to push away the peel from the plantain to take the peel off. If the peel is sticky and you have some pieces that are stuck on, you can use a potato peeler to get the rest of it off nicely. Cut the plantain into thick slices, about 1 inch thick.
Next, heat up the oil on medium heat to medium-high heat. You will need to use a large skillet or a large frying pan and add enough oil to cover the bottom of the pan and have a shallow layer of oil in the pan.
Add the pieces of plantain into the oil. Cook on one side until bright yellow, about 3-4 minutes, then flip. Once the other side is also bright yellow in color, you can flip them on their sides to makes sure the whole thing is cooked through. If they are starting to brown in color too quickly, turn the heat down a little bit.
Take the plantain pieces out of the oil and place on a cutting board, but keep the oil on the stove. Use the bottom of a glass or mug to smash the pieces into disks.
Add the flattened plantains back into the skillet of hot oil to fry again for a second time. This time you want to fry until they get crispy, about 4 more minutes on each side.
Once they are crispy and golden brown on each side, place them on a paper towel-lined plate to soak up any excess oil, and sprinkle salt immediately as each one comes out of the pan! Serve and enjoy.