Rinse salted fish thoroughly, place in a container and pour in enough cold water to cover by 2 inches of water.

Cover and refrigerate, changing water 2 or 3 times a day, until fish is softened and no longer tastes overpoweringly salty, 1 to 2 days.

Flake or dice enough fish to measure 1/3 cup; save the remainder for another use (It's excellent in soup).

Place fish in a medium bowl and add pork; stir until mixed.

Add eggs, onion, garlic, broth, sugar, pepper and 1 tablespoon of the fish sauce, and whisk again.

Heat oil in a medium skillet over medium heat.

When hot, pour in egg mixture, cover the skillet and cook until the bottom is very brown, about 5 minutes, lifting edges with a rubber spatula occasionally and tilting the pan to let uncooked egg run underneath.

Preheat the broiler.

Place the skillet under the broiler and cook until pork is cooked through and egg is set and browned on top, 2 to 3 minutes.

Line a platter with lettuce leaves.

Loosen omelet around edges and bottom with a spatula and slide or invert onto the platter.

Meanwhile, toss mango, cucumber and bell pepper with lime juice and remaining 1 tablespoon fish sauce. Serve with omelet.