Plantains can be a bit difficult and tricky to peel, especially when still in their green, unripe state.
First, make sure your plantains are at room temperature, as cold plantains can be twice as hard to peel (which pretty much means darn near impossible!) so if you stored your plantains in the fridge, make sure you take them out at least a couple of hours before you begin. Another trick is to soak the plantains in hot tap water for a few minutes to warm them up.
Cut off both ends of the plantains and discard the tips.
Hold your plantain firmly in one hand and, with the tip of a sharp knife, slit the peel along the entire length of the fruit in 3 different locations. Cut only as deep as the peel is thick; you don’t want to be cutting into the flesh of the fruit.
To remove the peel, insert the tip of your fingers between the flesh and peel and delicately run it up and down the fruit until the peel comes loose. The peel will come off in sections.
Don't worry if a few small chunks of flesh come off with the peel; likewise, use a paring knife to remove any potential peel remnants left on the flesh.
Cut the plantains into 10 to 12 thick slices, either straight or on a diagonal.
Heat the coconut oil in a large skillet set over medium heat.
When the pan is hot enough, add the plantain and fry the slices for about 2 minutes, or until they turn crisp and golden brown. Flip the slices and continue cooking until that side also turns golden. Remove the plantain to a cutting board and immediately flatten them down with a flat object such as a small saucepan, a flat bottomed drinking glass, turner or spatula. Return the plantain to the skillet and fry for a second time, about 1 minute per side this time.
Remove the tostones from the skillet and sprinkle generously with salt.