- Blanch bok choy in boiling water for 1–2 minutes and immediately place in an ice bath to stop cooking. Set aside.
- Season flounder with salt and pepper.
- Place fish in steamer and steam for 8–10 minutes, until flesh is flaky and tender.
- While fish is steaming, heat canola oil in a hot pan and add onion, 1 teaspoon garlic, and peppercorns. Add salt and pepper.
- When onion has softened, add black vinegar and chili oil. Set aside.
- In a separate pan, reheat bok choy and add remaining garlic and stock or wine.
- To serve, place bok choy on bottom of a serving tray. Place steamed flounder on top, and pour onion mixture and sauce over flounder. Garnish with chopped leeks and citrus segments and drizzle with sesame oil.