Heat 1 tablespoon of vegetable oil in a large skillet over medium-high heat. Add the tofu cubes and cook for 6 to 8 minutes, turning occasionally until lightly golden on several sides. Remove the tofu to a plate and set aside.
Add the remaining tablespoon of vegetable oil to the same skillet. Stir in the minced garlic and cook for 30 seconds until fragrant.
Add the mixed frozen vegetables and cook for 3 to 4 minutes, stirring often, until they are heated through.
Add the chilled rice to the skillet. Break up any clumps with your spatula and stir-fry for 4 minutes until the rice is hot and starting to crisp in spots.
Return the cooked tofu to the pan. Pour in the soy sauce and sesame oil, then add the black pepper. Stir everything together for 2 minutes so the rice absorbs the sauces evenly.
Remove the skillet from the heat and stir in most of the sliced scallions. Reserve a small handful for topping each plate.