Preheat the oven to 350 degrees F (175 degrees C). Pour water into a 9x13-inch baking dish.

Stir cream cheese in a bowl until smooth. Fold brown rice, spinach, black beans, diced tomatoes with green chiles, minced onion, cumin, and oregano into cream cheese until evenly mixed.

Halve bell peppers lengthwise. Remove and discard stems, seeds, and membranes.

Fill each pepper half with about 3/4 cup rice mixture; arrange into the prepared baking dish. Sprinkle cheese evenly over peppers.

Bake in the preheated oven until peppers are tender, 35 to 45 minutes.