Preheat oven to 350 degrees. Place pepper halves on a 13 by 9-inch baking sheet in a single layer. Bake until tender crisp, about 10 - 15 minutes.
Meanwhile make the filling. Heat olive oil in a 12-inch non-stick skillet over medium-high heat. Add onion and saute 3 minutes. Add garlic and saute 30 seconds.
Scoot mixture to one far side. Add ground turkey and break into chunks, season with salt and pepper. Let cook while tossing and crumbling, until nearly cooked through. Add corn then finish cooking turkey through.
Remove from heat. Stir in diced tomatoes, tomato sauce, rice, black beans, chili powder, cumin and season with salt and pepper to taste.
Stir in 1/2 cup of the Mexican cheese blend and the cilantro.
Spoon filling into peppers filling them heaping full (you can press down slightly to fit more in). Sprinkle remaining 1 cup cheese blend over tops.
Return to oven and bake until cheese is nicely melted and peppers are softened to liking, about 8 to 10 minutes longer.