Combine the garlic, paprika, cumin, coriander, oregano, thyme, if using, cayenne, salt, and pepper in a small bowl. Add the olive oil and vinegar and stir to make a paste. Smear the paste on both sides of the pork chops and place a lemon slice on top of each. Let the chops sit in the fridge for 30 to 45 minutes, or longer (or skip the fridge if time is tight).
Heat a large skillet over medium-high heat until very hot. Add a couple of teaspoons of olive oil and when the oil just starts to smoke, add the pork chops, lemon slice side down. You may have to do this in 2 batches, using a bit more olive oil if the pan is crowded. Let the chops sear without moving them until nicely browned on the bottom, about 4 minutes.
Turn the chops, keep the lemon slices in place, and sear the other side, again without moving them, for another 4 minutes or so, until nicely browned on the underside and a meat thermometer inserted into the middle of a chop registers 150°F (the meat will continue to cook after it leaves the pan).
Transfer the chops to a serving plate or cutting board and let sit for 4 or 5 minutes before serving whole, or in slices. Sprinkle with parsley or additional paprika if desired, and serve with lemon wedges for squeezing over the pork.