Heat your griddle or pan with enough oil to cover the bottom of the pan over medium-high heat. While the pan is heating, slice your plantain in 1/2 " rounds. Add to the griddle and cook until a golden sear is reached (about 1.5 minutes), flip and cook the same on the other side. Remove plantain rounds, and flatten in a meat tenderizer or a rolling pin. Add a little more oil to the pan and add in the plantain disks, cooking on each side for another minute. Remove tostones, and drain on paper towels. Sprinkle with salt and enjoy!