In small bowl, stir together soy sauce, Shaoxing wine, water and sugar; set aside close to stovetop. Arrange remaining ingredients (except oil) on rimmed sheet in bowls and place close to stovetop.
Heat wok or large cast-iron pan over high heat. Add oil and heat until hazy. Add pork belly and cook, stirring, until browned and crispy, 2 to 4 minutes; remove fat to a bowl, leaving 1 tbsp in pan. Reduce heat to medium; add garlic and chilies and cook, stirring, until garlic is light brown, 45 to 60 seconds.
Add cabbage and drizzle over soy sauce mixture. Return to high heat, cover and cook for 1 minute. (Or if pan is too full, carefully slide mixture into large bowl, quickly toss and return to pan.) Sprinkle in green onions and cook, stirring, for 1 more minute.
Drizzle over vinegar; toss and sprinkle with peanuts (if using). Gently stir, or slide into large bowl again to toss and return to pan; the cabbage should be crunchy and lightly caramelized. Remove from heat, sprinkle with salt (if using) and garnish with sesame seeds (if using).