Preheat oven to 425 degrees.
In a blender, combine tomatoes, Smoky Chipotle EVOO, jalapeno, half the onions, and 2 garlic cloves; puree. Season with salt. Pour sauce into a 9-by-13-inch baking dish and set aside.
In a medium bowl, combine beans, cornmeal, ½ cup cheese, remaining onions, minced garlic, cumin, and ¾ cup water; season with salt and pepper. Dividing evenly, stuff poblano halves with bean mixture and place on top of sauce in a baking dish.
Sprinkle poblanos with remaining ½ cup cheese and cover baking dish tightly with aluminum foil. Bake until poblanos are tender, about 45 minutes. Uncover, and continue to cook until sauce is thickened slightly and cheese is browned, 10 to 15 minutes more.
Let cool 10 minutes. Top with key lime sour cream.