Lightly coat a medium saucepan with sesame oil, and place pan over low to medium heat. Slice tempeh into 1" strips and place in saucepan. As oil begins to simmer, stir tempeh to coat; add soy sauce and continue stirring, adding sesame oil as needed. Remove from heat after 1 minute; add vinegar to taste. If desired, garnish with black sesame seeds. Best served warm. All measurements are approximate--I simply drizzled the oil, soy sauce and vinegar to taste. I recommend using three grain tempeh, which has a rich, nutty flavor. This makes a good side dish or salad topping.