Position a rack in the center of the oven and preheat to 350 degrees F. Spray a 9-inch pie pan with cooking spray.
Put the graham crackers, brown sugar and salt in the bowl of a food processor. Process until the graham crackers have broken down into fine crumbs. Add the coconut oil and process until combined; the mixture will resemble very wet sand. Press the mixture into the bottom of the prepared pan, using the back of a flat-bottomed glass or measuring cup to press the crust firmly into the bottom and up the sides of the pan.
Combine the egg yolks and condensed milk in a large bowl and whisk to combine. Add the lime juice and tequila and whisk until smooth.
Spread the filling evenly over the crust. Bake until the filling is just set and only slightly jiggles in the center, 20 to 25 minutes, rotating the pan once halfway through baking. Let cool slightly on a wire rack for 20 minutes, and then chill in the refrigerator until completely cooled, at least 4 hours and up to overnight.
Right before serving, whisk the heavy cream and confectioners' sugar in a large bowl on medium-high speed until soft peaks form, about 2 minutes. Add the orange liqueur and whisk until the cream reaches medium stiff peaks, 1 to 2 minutes, being careful not to overmix.
Remove from the refrigerator and sprinkle with flaky sea salt. Spread the whipped cream on top, then cut into 8 to 10 pieces and serve.
When measuring flour, we spoon it into a dry measuring cup and level off the excess. (Scooping directly from the bag compacts the flour, resulting in dry baked goods.)