Begin by pressing your firm or extra-firm tofu. Place it between layers of paper towels and set a heavy skillet on top. Let it sit for about 10 minutes to drain excess moisture, then cut into 1-inch cubes.

In a mixing bowl, toss the cubed tofu with cornstarch and a sprinkle of salt. Allow the tofu to sit for 5 minutes.

While the tofu is resting, whisk together sweet chili sauce, soy sauce, rice vinegar, minced garlic, ginger, sesame oil, and optional red pepper flakes until smooth.

Heat vegetable oil in a non-stick skillet over medium heat. Add the tofu cubes and fry for about 3-4 minutes on each side until golden brown.

Lower the heat and pour the prepared sauce over the crispy tofu. Gently toss to coat, simmer for an additional 1-2 minutes.

Remove from heat and transfer to a serving dish. Garnish with sliced green onions and sesame seeds, then serve over jasmine rice or quinoa.