Place the bell pepper halves, cut sides down, on a microwave-safe dish; cover with plastic wrap. Microwave at HIGH 3 minutes and 30 seconds or until pepper halves are crisp-tender. Let stand, covered, 3 minutes (peppers will soften).
While the peppers cook, heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add beef to pan; cook 3 minutes, stirring to crumble. Add water and seasoning, and stir to combine. Cover, reduce heat, and cook 5 minutes or until done.
While beef cooks and peppers stand, cook the potatoes in microwave according to package directions, omitting salt and fat.
Spoon 1/2 cup beef mixture into each pepper half; top each with 2/3 cup potatoes. Sprinkle each pepper half with 1 tablespoon cheese. Garnish with black pepper, if desired.