Slice the block of tofu in half lengthwise, then cut crosswise into 3/8 inch (1cm) slices.
Heat a nonstick or cast iron skillet over medium-high heat. Once hot, add the oil, and spread it around the pan. Add the tofu slices.
Fry for 5-7 minutes until golden brown, rotating the pan as needed so the tofu slices cook evenly. Do not disturb the tofu until they’ve fried for a few minutes. Flip and then cook for another 5 minutes, until golden on the other side.
For the dipping sauce:
To make the dipping sauce, heat a tablespoon of oil in the pan you used to cook the tofu (no sense in dirtying another pan!)
Add the cilantro, scallions, garlic, and chili flakes to a small heatproof bowl, so all the ingredients are side by side. Drizzle the hot oil over the top, paying special attention to the garlic and chili flakes. Use a rubber spatula to scrape out all the oil.
Stir in the water, light soy sauce, sugar, and rice vinegar. Serve with the pan-fried tofu.