In a large bowl, add 4 cups of water with 1 tbsp of salt and stir. Add the plantain slices to the bowl and let it soak for 25 minutes.
Drain the plantain slices and pat them dry with paper towels to remove as much moisture as possible. Add them to a dry bowl and toss with 1 tbspof olive oil.
Select AIR FRY and set the time and temperature to 350°F for 15 minutes.
Once the basket is preheated, add the pieces of plantain in a single layer and leave some space between each slice to allow air flow. (You may have to cook in two batches.) Turn the plantains when the "Turn Food" notification sounds.
Carefully remove the plantains from the air fryer basket and place on a cutting board. Place a piece of parchment paper over top of the plantain slices and use a small plate or glass to press down on each piece and flatten them.
Spray the plantains with cooking spray or brush them with oil. Flip them over and coat the other side in oil.
Select AIR FRY and set the time and temperature to 400°F for 8 minutes.
Once preheated, add the plantains in a single layer and turn them halfway through cooking. (You may have to cook in two batches.)
Sprinkle with salt and serve with your favorite dip.