If your rice isn't cooked already, do so now and set aside.
Preheat the oven to 375 degrees Fahrenheit.
Add the diced onion and olive oil to a large skillet and saute over medium heat.
Once it starts to look translucent, add in the garlic and saute an additional 2-3 minutes.
Add in the corn and saute to defrost.
Add in all remaining ingredients and mix well.
Let simmer over low heat. Meanwhile, wash and halve the peppers and remove the seeds.
Add to a large (9 x 13) baking dish. Taste the filling and adjust flavors as desired. Scoop the filling into each pepper, using about 1/3 cup worth in each half, though it depends on the size of the pepper.
Top with vegan cheese if desired (I like the brand violife or the Chao creamy original slices). Otherwise, just drizzle with olive oil so they don't dry out.
Bake, covered with foil, for 30 minutes, then remove the foil and bake an additional 15-20 minutes or until the peppers have softened and the filling has browned lightly. If you prefer softer peppers, just roast for longer, closer to 1 hour total.
Remove from the oven and serve with cashew queso (highly, highly recommend!), avocado, chopped cilantro, and fresh lime.