Preheat the oven to 450°F. Line a baking sheet with parchment paper and set aside.
In a medium bowl, add the tofu chunks, tapioca flour/starch, salt and 1 tablespoon of olive oil. Toss to coat the tofu well and then place onto the baking sheet. Bake for 25 minutes.
Meanwhile, cook the rice according to package instructions. Chop the bell pepper into medium-small pieces, removing the seeds and stem.
Heat a large skillet over medium heat and add the other tablespoon of olive oil and the peppers. Sauté the peppers until they soften and start to brown. Add the pineapple to the skillet and sauté another few minutes. Reduce the heat to low and add the sweet and sour sauce. Add the baked tofu. Toss everything together until the tofu is well coated in the sauce and serve over brown rice. Garnish with green onion.