Preheat the oven to 220C, fan-forced. Line an oven tray with baking paper. Cut the unpeeled potatoes into wedges. Combine the Chinese barbecue seasoning and 2 tsp oil in a large bowl and season with salt and pepper. Add the potato wedges and toss to coat.
Step 2 — Roast wedges
Put the potato wedges on the lined tray and roast, turning halfway through cooking, for 20 mins or until browned and tender.
Step 3 — Prep greens
While the wedges are roasting, halve the zucchini lengthwise, then thinly slice on an angle. Quarter the pak choy lengthwise, then cut into thirds.
Step 4 — Coat fish
Pat the fish dry with paper towel. Put the fish, skin-side down, in a shallow dish. Spread with 2 tsp kecap manis and scatter over the sesame seeds, pressing lightly to create a crust.
Step 5 — Cook fish
Heat 2 tsp oil in a small frypan over medium heat until hot. Cook the fish, skin-side down, covered, for 3 mins. Turn and cook, uncovered, for 4 mins or until cooked through (cooking times may vary depending on thickness of fillets).
Step 6 — Stir-fry greens
Meanwhile, heat 2 tsp oil in a medium frypan over high heat. Stir-fry the zucchini and pak choy for 2 mins. Add the sesame oil, remaining kecap manis and 1 tsp soy sauce and stir-fry for a further 1 min or until the vegetables are just tender. Divide the potato wedges, greens and fish among bowls to serve.