In a liquid measuring cup or small bowl, stir together the soysauce, vinegar, sugar and chile sauce until the sugar dissolves.
In a large skillet, heat the oil over medium-high. Add the tempeh, season lightly with salt, and cook, stirring occasionally, until mostly golden, 7 to 9 minutes. Add more oil as needed if the pan looks dry or the tempeh is burning.
Reduce the heat to low, give the sauce another stir, add the sauce to the skillet and cook, stirring constantly, until the sauce is thickened and glossing the tempeh, about 1 minute.