Fill a medium saucepan three-quarters full with water and bring to the boil. Cook the rice in the pan of boiling water for 23 mins. Add the peas, return to the boil and cook for 2 mins or until the rice is tender. Drain.
Step 2 — Make stir-fry sauce
While the rice is cooking, juice the orange. Crush or finely chop the garlic. Combine the garlic, orange juice, mirin, 1½ tsp Chinese barbecue seasoning, 2 tsp soy sauce and 1 tsp honey in a bowl.
Step 3 — Prep ingredients
Cut the spring onions into 5cm lengths. Coarsely chop the pak choy, keeping the stems and leaves separate. Thinly slice the chilli, removing the seeds if less heat is desired (you can reduce or omit the chilli, if you prefer). Cut the fish into 3cm chunks.
Step 4 — Coat and cook fish
Combine the cornflour and remaining Chinese barbecue seasoning in a bowl and season with salt and pepper. Dust the fish with the cornflour mixture and shake off the excess. Heat 1 tbs oil in a medium deep frypan over medium heat. Cook the fish for 3½-4 mins each side until golden and cooked through (handle gently when cooking to prevent the fish breaking up). Remove from pan.
Step 5 — Start stir-fry
Wipe the frypan clean, then heat 2 tsp oil in the pan over high heat. Stir-fry the spring onion and pak choy stems for 2 mins. Add the pak choy leaves and stir-fry sauce and bring to a simmer. Reduce the heat to medium-high and cook, stirring occasionally, for 2 mins or until the sauce is slightly reduced and the pak choy is just tender.
Step 6 — Finish stir-fry and serve
Add the fish to the vegetables and sauce and very gently stir to coat the fish with the sauce. Divide the rice, peas and fish stir-fry among bowls. Scatter with the chilli, if desired, to serve.