1. Line an 8-inch springform pan with parchment paper.
2. In a food processor, pulse the pretzels, graham crackers, sugar, and salt into semi-fine crumbs. Add the butter and pulse until the mixture holds together when pinched. Press about ⅓ of the crumbs into the bottom of the prepared pan. Be sure to pack it in tightly. Freeze 10 minutes.
3. Spread half the ice cream (about 1 ½ pints) over the crust. Top evenly with half the chocolate fudge sauce and ⅓ of the graham-pretzel mixture. Cover and freeze 30 minutes to 1 hour. Remove from the freezer, add the remaining half of ice cream, remaining half of chocolate fudge sauce, and remaining ⅓ of graham-pretzel crumbs. Cover and freeze for 4-6 hours or preferably overnight.
4. In a microwave-safe bowl, melt together the chocolate and coconut oil. Remove the cake from the freezer and release it from the springform pan. Pour the chocolate over the cake. Garnish with more pretzels and graham cracker bites. Freeze until firm, about 10 minutes.
5. Remove the cake from the freezer, slice, and serve immediately.