Line an 8x8-inch baking pan or small tray with parchment paper.
Arrange the pitted Medjool dates in a single layer, slightly overlapping. Using your hands or the bottom of a glass, press the dates together to form an even rectangle about ¼-inch thick.
Spread the almond butter evenly over the pressed date layer.
Sprinkle the chopped roasted almonds over the almond butter, gently pressing them in so they adhere.
In a microwave-safe bowl or using a double boiler, melt the dark chocolate chips with the coconut oil until smooth.
Pour the melted chocolate over the almond layer and spread evenly with an offset spatula or the back of a spoon.
Finish with a generous sprinkle of flaky sea salt.
Place the pan in the freezer for 1 hour, or until the chocolate has completely set.
Remove from the freezer and let the bark sit at room temperature for 3–5 minutes before slicing or breaking into pieces.
Serve immediately or store in the freezer for later.