Lightly oil a large baking sheet. Toss the pecans with the salt and cayenne into a small bowl.
Place the sugar in a heavy skillet or saucepan and cook over medium heat, stirring gently until the sugar starts to melt. Stop stirring and continue cooking, swirling the skillet or pan often until the sugar cooks to a dark golden caramel.
Add the pecan mixture and carefully stir to coat the nuts with caramel. Pour onto the baking sheet and spread evenly with a knife. Cool completely. Crack the praline into pieces, then finely chop on a cutting board.