In a small bowl, mix cilantro, 1/2 tsp cumin, lemon zest, juice from half of the lemon, olive oil, garlic, chili flakes, and salt and pepper to taste. Set aside.
Score each filet and season both sides with salt, pepper, and cumin
Add some oil to a pan and heat on medium-high. Once hot, place both filets in pan (skin side down first!) and cook on each side 4-6 minutes
Plate Barramundi, topping each with chimichurri. Serve with lemon wedges from the other half of the lemon.