Line a clean work surface with a 4-foot length of parchment paper. Put sugar, cream, and salt in a 3-quart heavy-bottomed saucepan. Stir mixture over medium heat until sugar dissolves, then allow it to come to a boil without stirring. It will now take 15-20 minutes to finish cooking the pralines.
The sugar syrup will foam up with large bubbles, but these will soon subside. Cook syrup until it reaches the soft ball stage, 238° on a candy thermometer. (Or drop about 1⁄2 tsp. syrup into a small bowl of cold water; it should form a teardrop-shaped ball at the bottom of the bowl. Roll the ball between your fingers; if it holds together in a soft ball, the syrup is ready to remove from the heat.)
Remove syrup from heat, add pecans, and stir briskly for 1 minute. Working quickly, drop mixture, 1 heaping tbsp. at a time, onto parchment paper. Allow to cool completely, then remove from paper.