Whisk together the salt, 1/4 cup of the smoky maple seasoning, 1/4 cup of the sugar and 4 cups water in a medium saucepan. Bring to a simmer, whisking, until the salt and sugar dissolve. Pour in 4 cups of cold water and mix thoroughly, then transfer the brine to a large container with a lid and cool to room temperature. Add the pork chops to the brine, cover and refrigerate 8 to 10 hours.
Prepare a grill for medium-high heat.
Remove the pork chops from the brine and pat dry with paper towels. Lightly rub some oil into the chops, then season all over with 2 tablespoons smoky maple seasoning. Grill until the pork chops are well marked and charred, 7 to 9 minutes. Flip and continue to grill until cooked through and an instant-read thermometer registers 145 degrees F, 4 to 6 minutes more. Let rest under tented foil while you cook the apples.
Put a large cast-iron skillet on the grill. Juice one of the lemon halves into a small bowl. Add 1 teaspoon of the lemon juice and the remaining 1/4 cup sugar to the skillet and stir with a heatproof spatula until the mixture looks like wet sand. Cook with the lid open, stirring frequently, until the sugar melts and deepens to amber, about 8 minutes. Add the butter and stir until melted. Once the foam subsides, add the apples, cover the grill and cook, gently stirring occasionally and coating the apples in the caramel, until the apples are crisp-tender, about 8 minutes. Remove the skillet from the heat and, being careful of splattering, add the remaining lemon juice and a pinch of smoky maple seasoning and stir gently.
Arrange the pork chops on a platter and top with the apples. Use a fine rasp grater to zest the other lemon half over the dish. Sprinkle with chives if using.
Brining pork chops infuses them with tons of flavor and helps make them tender and juicy-- just like a perfectly cooked well-marbled steak.