Preheat the oven to 200C (400F).
In a small bowl, whisk together the harissa paste, honey, lemon juice, 1 tablespoon of olive oil, and ground cumin to create the glaze.
On a large rimmed baking sheet, toss the sliced peppers, zucchini, and chickpeas with the remaining 1 tablespoon of olive oil, salt, and pepper.
Spread the vegetables in an even layer and roast in the oven for 10 minutes.
Remove the tray from the oven and move the vegetables to the perimeter to create space in the center.
Place the barramundi fillets onto the tray and brush the honey harissa glaze generously over each fillet.
Return the tray to the oven and roast for 10 to 12 minutes, or until the barramundi reaches an internal temperature of 63C (145F) and flakes easily with a fork.
Garnish with fresh cilantro and serve immediately.