01 - Combine soy sauce, rice vinegar, maple syrup, sesame oil, and black pepper in a mixing bowl. Add the tempeh cubes, toss to coat evenly, and allow to marinate for at least 10 minutes.
02 - In a shallow dish, whisk together cornstarch and salt. Remove tempeh from marinade, reserving excess liquid, and roll cubes through the cornstarch mixture until evenly coated.
03 - Heat 1–2 tablespoons neutral oil in a large non-stick skillet or wok over medium-high heat. Arrange tempeh cubes in a single layer and fry 8 minutes, turning occasionally, until golden and crispy. Transfer to a plate lined with paper towel.
04 - If necessary, wipe out the skillet. Add 2 tablespoons oil and heat over medium. Sauté garlic and chopped chili for 1 minute until fragrant.
05 - Pour in chili sauce, soy sauce, rice vinegar, maple syrup, the reserved marinade, and water. Stir well and bring to a simmer.
06 - Add the cornstarch slurry while stirring. Cook 1–2 minutes until the sauce has thickened.
07 - Return crispy tempeh to the skillet. Toss well to coat in the sauce and cook for 2 minutes to fully heat through.
08 - Transfer tempeh bites to a serving plate. Garnish with scallions, toasted sesame seeds, and cilantro if desired.