Heat 2 tablespoons of vegetable oil in a large pan over medium heat. Add the tofu cubes and cook for 2-3 minutes on each side or until golden brown. Remove from the pan and set aside.
In the same pan, heat the remaining tablespoon of oil. Add the garlic, ginger, bell pepper, and carrot. Cook for 5-6 minutes until the vegetables are tender.
Once the vegetables are tender, add the chiles and green onions to the pan and cook for another 2-3 minutes.
In a small bowl, whisk together the cornstarch and a few tablespoons of water until no clumps remain.
Add the rest of the water, soy sauce, Shaoxing wine, hoisin sauce, brown sugar, and sesame oil. Add this sauce to the pan with the vegetables.
Add the cooked tofu back into the pan and stir to combine everything. Cook for a few more minutes until everything is heated through and the sauce has thickened.
Lastly, stir roasted peanuts and peppercorns into the kung pao tofu mixture until it is well combined. Serve immediately while hot with extra green onions, peanuts, or chile oil on top.