Special equipment: a 10-inch pie dish
Place the chocolate wafer cookies in a food processor along with the salt; process until the cookies are the texture of smooth sand. Transfer the cookie crumbs to a bowl and set aside.
Melt the chocolate chips in the top of a double boiler or in a microwave. Whisk in the coconut oil and 1 tablespoon of the crème de menthe until smooth.
Stir 2/3 cup of the chocolate mixture into the cookie crumbs until combined. Press the crumbs evenly into the bottom and up the sides of a 10-inch pie dish. Use the bottom of a measuring cup to tightly pack the crumbs to form the crust. Freeze for 10 minutes to set the crust.
With a small offset spatula, spread the remaining chocolate mixture over the base of the crust and 1/2 inch up the sides. Freeze for another 10 minutes to set the chocolate.
In the bowl of a stand mixer fitted with the whisk attachment, whip together the heavy cream, confectioners' sugar and the remaining 1/4 cup crème de menthe on high speed until stiff peaks form. Spoon the whipped filling onto the pie. Freeze for at least 4 hours or overnight to set completely. Remove from the freezer twenty minutes before serving.
When ready to serve, drizzle the pie with chocolate syrup and garnish with mint leaves.