Heat a 10-inch non-stick skillet over low. Place pork medallions in a medium bowl, drizzle with oil, sprinkle lightly with salt and pepper, and toss to coat. Mix apple cider, chicken broth, soy sauce, and ginger in a Pyrex measuring cup. Mix cornstarch and water in a small bowl. A couple of minutes from cooking, turn on vent fan and increase heat under pan to high. When pan is very hot add medallions to skillet. Cook, without turning until well browned on one side, 3 to 4 minutes. Turn and continue to cook until well browned and cooked through, 3 to 4 minutes longer. Transfer to a plate to rest. Add apple cider mixture to pan and cook until reduced by half, adding any pork juices to the sauce, a couple of minutes. Whisk in cornstarch mixture and continue to cook until sauce is thick enough to coat the pork, almost instantly. If sauce is too thick, simply add water until desired consistency. Serve medallions with a little sauce spooned over each portion.