Combine all sauce ingredients in a bowl.
Boil potatoes in salted water with 2 teaspoons of lemon juice (or mild vinegar).
Drain in colander and set aside. In a large skillet over medium heat, fry potatoes until golden brown.
Add sauce, simmer until thickened, stirring often for even coating. Off heat, stir in sesame seeds, garnish with green onions, and serve immediately. Enjoy your meal!