In a small bowl, combine the scallions, cilantro, lime juice, olive oil, chile, and Maggi sauce, and stir to mix well. Set aside for at least 15 minutes. Season with salt to taste, if need be.
For the fish:
Sprinkle the fish fillets with the salt and pepper. Spread flour on a large plate and coat each fillet thoroughly on both sides.
Heat 1/4-inch of vegetable oil in a large skillet over medium-high heat until hot but not smoking. Add the fish, in batches to avoid crowding, and sear for about 3 minutes, until crisped and browned on the bottom. Don’t fiddle with the fillets, let them brown so they don’t stick to the bottom and can be released. Turn and brown for about 3 minutes on the second side. The fish is ready when the thickest part is cooked through and it flakes easily with a fork. Put the fish on a paper towel-lined baking sheet. Keep warm in a low (250°F) oven, if you won’t eat it in the next 10 minutes.
Transfer the fish to a platter and pour the sauce on top. Or, you can do as I do, flake the fish and serve drizzled with the sauce, ready to make tacos. Serve with corn tortillas.