Press the tofu for at least 15 minutes to remove excess moisture, then cut it into 1-inch cubes.
Toss the tofu cubes in soy sauce and cornstarch until evenly coated. This helps create a crispy exterior.
Heat a large non-stick skillet over medium-high heat and add 2 tablespoons of vegetable oil. Once shimmering, add the tofu cubes in a single layer.
Fry the tofu for 4-5 minutes, turning occasionally, until golden and crispy on all sides. Remove and set aside on a paper towel-lined plate.
Lower the heat to medium. Add the minced garlic and grated ginger to the same skillet, cooking for about 30 seconds until fragrant.
Add the sliced bell pepper and zucchini to the skillet. Stir-fry for 3-4 minutes until vegetables are lightly charred and tender, seasoning with a splash of soy sauce.
Return the crispy tofu to the skillet. Drizzle with toasted sesame oil and toss everything together to coat evenly. Cook for another minute to meld flavors.
Remove from heat and let sit for 2 minutes. Serve hot, garnished with optional sesame seeds or scallions for extra flavor and presentation.