For the barramundi, season both sides of the barramundi fillets with salt and freshly ground black pepper and brush with one tablespoon of the grapeseed oil.
Sprinkle the fillets with cumin and sumac.
Heat the remaining tablespoon of grapeseed oil in a frying pan until hot, then add the barramundi fillets. Fry for 2-3 minutes on each side, or until cooked through, then remove from the pan and keep warm.
Add the shallots and fry for 2-3 minutes, then add the wine and simmer until reduced by at least half the volume.
Add the fresh chives and oregano and season, to taste, with salt and freshly ground black pepper.
For the avocado hummus, place the avocados and lemon juice into a food processor and blend until smooth.
Add the olive oil, garlic, tahini, cumin and sumac and blend to the consistency of mayonnaise.
Add the sesame seeds and stir.
To serve, place two barramundi fillets onto each of four plates and drizzle with the white wine and herbs sauce. Serve with a spoonful of avocado hummus alongside.