Slit each date with a knife and remove the pit.
Fill each date with peanut butter. You may need more or less depending on how big your dates are.
Next stuff each date with peanuts, as many as you can fit. Pushing them down into the peanut butter.
Place the dark chocolate and the coconut oil in a microwave safe bowl and melt in the microwave for 1 minute. Stir and then continue melting in 15 second increments, stirring between each. It shouldn't take longer than 1-2 minutes total.
With the opening facing down (into the chocolate) Dip each date into the melted chocolate. You could also use a spoon and lather the melted chocolate over the date. I prefer to dunk for full coverage.
As soon as the dates are coated, sprinkle salt flakes over top.
Place dates in the fridge and allow the chocolate to harden.
Once set, transfer to an airtight container and store in the fridge for up to 7 days.