Preheat the oven to 375°F and grease a baking dish big enough to hold the peppers with oil or butter.
Cut poblano peppers in half lengthwise and discard the seeds and membranes. Place the peppers cut side up in the prepared dish.
In a large bowl,mix the turkey, grains, tomato sauce, smoked paprika, cumin, coriander, chili powder, salt and pepper. Fold in green onions and cheese, reserving half to sprinkle on top. Spoon the stuffing into the peppers and sprinkle cheese overtop.
Pour just enough water in the baking dish to cover the bottom. Cover the peppers loosely with a lightly greased piece of foil (to help foil not stick to melted cheese) or compostable parchment paper.
Bake for 20 minutes, then uncover and bake for an additional 5 to 10 minutes to brown the tops. The filling should be heated through and the peppers softened.