Line a 9 x 9-inch baking dish with parchment paper. You'll need it to lift the bars out.
Make the first layer:
To the bowl of a food processor, add the almonds, pecans, and dates. Cover and process until a thick dough forms. Transfer it into the lined baking dish and press down to form the crust.
Melt the coconut butter and pour over the crust. Freeze for 1 hour or until firm.
Make the middle layer:
Add the dates and hot water to the food processor and process until a thick paste forms. Spread the date mixture over the first layer and return to the freezer while you make the next layer.
Make the top layer:
In a microwave-safe dish, combine the chocolate and coconut oil. Microwave in 30-second increments until melted, stirring with a fork until smooth. You can also use a double boiler for this.
Pour the chocolate over the first two layers and spread it evenly. Sprinkle coarse sea salt over the chocolate and freeze until set, about 2 hours.
Serve and storage:
Remove the dish from the freezer, let it sit on the counter for 5 minutes, then lift it out with the parchment paper. Slice it into 12 square bars.
Store leftover bars in an airtight container in the fridge for up to 1 week or in the freezer for up to 3 months.