Combine the egg whites and salt and heat until they stand in soft peaks. Slowly add the sugar, continuing to beat until the whites stand in stiff peaks. Sprinkle in the flour and pecans, and fold them in, using a rubber spatula or an electric mixer turned to the lowest speed for 3 or 4 seconds.
Shape the meringues on the parchment or foil-lined sheets using a pastry bag fitted with a 1/2 inch plain tip --- or use a teaspoon and form small mounds about 2 inches across, placing them about 1/2 inch apart. Double-pan the sheet and bake for about 20 minutes to dry out. Turn off the oven and let remain there for another 20 minutes to dry out further. Peel off the foil or parchment and let cool completely. In a dry climate, store at room temperature in a sealed container. If it's damp or humid, freeze for storage.