In a medium bowl combine egg, bread crumbs, green onions, 1 Tbsp. of the soy sauce, 1 Tbsp. of the sriracha sauce, the garlic, and ginger. Add ground pork; mix well. Shape into 18 meatballs.
Heat a 10-inch cast-iron skillet over medium 5 minutes. Add 1 Tbsp. of the vegetable oil; heat 1 minute. Add half of the meatballs; cook 5 minutes or until browned, turning occasionally. Remove meatballs. Repeat with remaining 1 Tbsp. vegetable oil and meatballs. Drain off fat.
Meanwhile, for sauce, in a small bowl combine remaining 2 Tbsp. soy sauce and 1 Tbsp. sriracha sauce, ketchup, brown sugar, sesame oil, and vinegar.
Add sauce to skillet; cook and stir over medium heat until bubbly, scraping up any crusty brown bits. Return meatballs to skillet. Cook, covered, over medium-low heat 5 minutes. Cook, uncovered, 5 minutes more or until meatballs are done (160°F), turning occasionally. Sprinkle with cilantro and sesame seeds.
Toast seeds in a dry skillet over medium heat, stirring frequently so they don't burn. Transfer to a bowl to cool.
(2 g saturated fat,
1 g polyunsaturated fat,
2 g monounsaturated fat),
27 mg cholesterol,
237 mg sodium,
8 g carbohydrates,
0 g fiber,
6 g sugar,
5 g protein.