Heat the oil in a large skillet on medium heat. Saute onions and peppers for about 5-10 minutes, until they soften.
Add the garlic and saute another minute.
Stir in the greens, cover, and steam until the greens begin to wilt, about 5 minutes.
In a bowl, use a fork to mash the tofu and soy sauce.
Increase the heat to high, add the scrambled tofu to the skillet and let sit for 3-4 minutes. Flip and let sit another 3-4 minutes. Tofu is done when it begins to brown.
Serve hot and garnish with sliced avocado if desired.