Combine sugar, cinnamon, salt, and water in a saucepan; cook, stirring, over medium heat until sugar is dissolved. Boil to 236° of a candy thermometer, or to soft ball stage.* Remove from heat; blend in vanilla. Add pecans and stir until mixture is creamy. Turn out onto waxed paper or silpat and use a fork to separate pecans.

*To Test for Soft Ball Stage
A small amount of syrup dropped into chilled water forms a ball, but is soft enough to flatten when picked up with fingers (234° to 240°).