Cut a small slice from the tips at both ends of the eggs to create a flat surface for them to stand upon. Slice each egg in half crosswise. Remove yolks; place in a small bowl and mash. Add scallion, cilantro, jalapeņo pepper, mayonnaise, and mustard; blend well. Spoon about 1 tablespoon of the yolk mixture into each egg half. Top each with cheese; sprinkle with chili powder. Cover; store in the refrigerator.