In a small bowl combine peanuts, cinnamon, and cayenne. Set aside.
Brush the inside of a medium sized heavy saucepan with vegetable oil. Add the sugar and water to the saucepan, cook over high heat, stirring occasionally with a wooden spoon, until it comes to a boil. Stop stirring, cover and cook for 3 minutes. Uncover, reduce heat to medium, and cook until the sugar is a light amber color. Stir in peanuts. This will greatly reduce the temperature of the sugar so work quickly. Once evenly mixed, pour mixture onto a sheet pan lined with a silicone baking mat or buttered parchment paper. Using a buttered spatula, spread thin. You will have to work quickly when pouring out and spreading the mixture in the pan. If necessary, in order to achieve single layer of peanuts, top with second sheet pan whose underside has been buttered. Cool completely and then break into pieces.
Recipe courtesy of Alton Brown