Preheat the oven to 400°F (200°C).
Pat the barramundi fillets dry with paper towels. Season the fish with salt and pepper on both sides.
Lightly oil a baking tray with vegetable oil and place the fillets skin-side down.
In a small bowl, whisk together soy sauce, sesame oil, rice vinegar, honey, minced garlic, grated ginger, and chili paste.
Taste the marinade and adjust sweetness or spice level as desired.
Pour the marinade over the barramundi fillets, making sure each piece is well coated.
Let the fish marinate for 10 minutes, allowing the flavors to infuse.
Place the marinated fish fillets on the prepared baking tray.
Roast in the preheated oven for 20 minutes, or until the fish is cooked through and the skin is crispy.
For extra crispy skin, you can broil the fish for the last 2-3 minutes of cooking, but watch carefully to avoid burning.
Once the fish is done, remove it from the oven and transfer the fillets to serving plates.
Garnish with sliced spring onions, fresh cilantro, and sesame seeds. Serve with steamed rice or sautéed vegetables.