Pat the tofu dry if needed and confirm it is cut into small cubes. Heat 1 tablespoon of vegetable oil in a large nonstick skillet over medium-high heat. Add the tofu in a single layer and cook, turning occasionally, until lightly browned on all sides, about 5–8 minutes. Transfer the tofu to a plate and set aside.
Add a second tablespoon of vegetable oil to the same skillet and reduce heat to medium. Pour in the beaten eggs and gently scramble until fully cooked, about 1–2 minutes. Transfer the scrambled eggs to the plate with the tofu and set aside.
Add the remaining 1 tablespoon of vegetable oil to the skillet and turn the heat back to medium-high. Add the minced garlic, minced ginger, diced yellow onion, chopped carrots, and the white/light green parts of the sliced scallions. Sauté, stirring often, until the carrots are tender but still slightly crisp, about 4–5 minutes.
Add the cold cooked rice, frozen corn, and frozen peas to the skillet. Break up any rice clumps with your spatula and stir everything to combine. Cook, stirring, for about 1–2 minutes to begin heating the rice and vegetables through.
Return the browned tofu and scrambled eggs to the skillet and stir to combine with the rice and vegetables.
In a small bowl, whisk together 2 1/2 tablespoons soy sauce, 1 1/2 teaspoons rice vinegar, 1 teaspoon sesame oil, and Sriracha to taste. Pour the sauce evenly over the rice mixture and stir-fry for 1–2 minutes more, until everything is heated through and the sauce is evenly distributed.
Remove from heat, garnish with the reserved dark green scallion slices, and serve the tofu fried rice hot.