Preheat the oven to 325˚F (165˚C). Line 2 muffin pans with 16 paper liners.

In a medium bowl, combine the graham cracker crumbs and sugar. Add the melted butter and mix well with a fork. Place about 1 heaping tablespoon crumb mixtures into each liner. With your fingers, press the mixture down to the bottom. Press hard. Bake in the oven for 10 minutes. Remove from oven and set aside to cool to room temperature.

In a large mixing bowl with an electric mixer fitted with a paddle attachment, beat the condensed milk and egg yolks for 5 minutes on medium speed. Mix in the zest, juice and salt until smooth. Pour about 3 tablespoons of mixture into each graham cracker crust. Bake in the oven for 7 – 8 minutes, until filling no longer jiggles.

Line a baking sheet with parchment paper.

Let the pies cool at room temperature for 20 minutes. Remove the pies to the prepared baking sheet, keeping the liners on. Transfer to the freezer and freeze for 2 hours. Remove the paper liners from the pies and carefully insert popsicle sticks. Place the pies back on the baking sheet. Freeze overnight.

To make the chocolate coating, in a small deep microwave safe bowl, add the chocolate and the vegetable oil. Mix with a spoon. Microwave for 15 seconds. Stir and microwave for another 15 seconds. Repeat the process until the chocolate is just melted and smooth. Dip the pies in the chocolate until completely covered. If needed, use a spoon to drizzle over. Gently shake to remove excess chocolate. Place them back on the baking sheet. Freeze for 2 more hours. Serve without thawing.