Take two cakes of hard tofu, and cut them in quarters, then divide the squares in half diagonally, then divide each piece in half "height-wise" to yield 32 bite sized pieces. Place a little peanut oil in a hot pan and stir fry the tofu pieces until they turn golden brown. Next sautee the garlic, ginger and chilis (if used) in a little oil, and then add the soy sauces and then all the other ingredients except the bean sprouts. Stir fry for about a minute, then add the cornstarch and continue to stir fry for a further minute.