Cut the tofu into 1/4 inch strips, then in half into squares. Line a colander with cheesecloth or a white paper towel. Allow to drain for 30 minutes.
To make the sauce, mix the garlic, ginger, soy sauce, mirin, sesame oil, black pepper, cornstarch, and half the green onion together. Set aside.
Heat a wide non-stick pan over medium high heat. Once hot, add 2 Tbsp of the cooking oil. Carefully add drained slices of tofu to pan. Fry until lightly browned. It will be more of a golden color. Carefully flip the slices with a spatula and brown on the other side. This will likely need to be done in batches depending on the size of your pan. Add more cooking oil as needed before the next batch.
Once all of the tofu is fried, return all to the pan. Stir the sauce to make sure the cornstarch is mixed in. Drizzle sauce into pan and stir to coat all the tofu slices. Cover pan and braise for 5 min. If the sauce gets too thick/dry, add a couple tablespoons of water.
Before serving, sprinkle with the remaining green onion and sesame seeds if desired. Serve hot over rice.
If avoiding corn, omit cornstarch or use an equivalent amount of another thickener such as arrowroot or tapioca starch.
Mirin is a sweet, Japanese cooking wine. It can be substituted with and equal amount of Chinese rice wine plus 1 tsp sugar.