Preheat the oven to 400° F.
Halve the potatoes lengthwise and, leaving shells 1/4 inch thick, scoop the pulp into a medium-size bowl.
Mash well, then mix in the ham, corn, scallions, yogurt, 1/2 cup of the cheese, the cumin, and red pepper.
Stuff the potato shells with the mixture, mounding it in the center.
Sprinkle with the remaining 1/2 cup cheese, dividing the total amount evenly, then arrange the potatoes in an ungreased 13" x 9" x 2" baking pan.
Bake, uncovered, for 25 to 30 minutes or until the potatoes are heated through.
Transfer to the broiler and broil 4 inches from the heat for 1 to 2 minutes or until lightly browned.