The title is a bit misleading here. These hands have all five fingers — it's just that only one is open. This gesture tends to indicate direction. One emoji turns around a couple of times so that it shows right, left, up, down. Use it as a guide.
In the Russian and Western cultures, it's common to point at something with the index finger — the name speaks for itself. However, there is a mysterious emoji which raises the middle finger. I wonder what can it possibly mean?.. Apparently, some metaphorical appeal to the divine forces. Or an allegory on some challenging path. So many interpretations!