Place peppers, garlic, pine nuts, cilantro and cheese in a food processor and process until combined. With the motor running, add the oil and process until emulsified and season with salt and pepper, to taste.
Heat grill to high. Brush each fillet on both sides with oil. Rub 1 side of each fillet with 1 tablespoon of the barbecue rub and place on the grill rub side down and cook until slightly charred and a crust has formed, about 2 to 3 minutes. Turn the fish over and grill for 3 to 4 minutes longer or until cooked to medium doneness. Top each fillet with a few tablespoons of the pesto and garnish with cilantro leaves.