Stir soy sauce, vinegar, and brown sugar in a small bowl until sugar is dissolved. Prick pork chops all over with a fork and place in a large Ziploc bag. Pour in half of marinade, seal bag, and turn to evenly coat pork chops. Set remaining marinade aside.
Let pork chops sit at least 10 mins, or chill up to 1 day.
Prepare a grill for medium heat. Remove pork chops from marinade. Season chops lightly with salt and grill, drizzling with reserved marinade and turning occasionally, Continue grilling until internal temperature is 145°F, ~6–8 mins.
Garnish pork chops with cilantro and jalapeños before serving.