01 - Cut the tempeh into 3/4-inch cubes.
02 - In a bowl, toss the tempeh cubes with cornstarch and salt until evenly coated.
03 - Heat neutral oil in a large nonstick skillet over medium-high heat. Add tempeh and fry for 6-8 minutes, turning occasionally, until all sides are golden and crispy. Remove tempeh and set aside.
04 - In a small bowl, whisk together soy sauce, maple syrup, rice vinegar, brown sugar, garlic, ginger, and chili flakes (if using).
05 - Pour the sauce into the same skillet and bring to a simmer over medium heat. Stir frequently until slightly thickened, about 2-3 minutes.
06 - Return the crispy tempeh to the skillet and toss to coat evenly, cooking for 2 more minutes until the glaze is sticky and glossy.
07 - Drizzle with toasted sesame oil.
08 - Serve hot, garnished with sesame seeds and green onions.