Coat a 12-by-17-inch rimmed baking sheet with cooking spray, and set aside. Place sugar, corn syrup, and 1/2 cup water in a medium saucepan. Cover; bring to a boil. Remove lid, and cook, swirling pan occasionally, until syrup registers 305 degrees (hard-crack stage) on a candy thermometer, about 10 minutes. Remove from heat, and carefully stir in lemon juice, extract, and food coloring.
Pour hot syrup onto prepared baking sheet, being careful not to touch syrup. Using a metal spatula coated with cooking spray, fold edges toward the middle (this will help cool the syrup). When it is cool enough to handle but still quite warm, using plastic gloves, strech and pull candy, folding it over onto itself before pulling again, until it is opaque and just starting to firm up, about 10 minutes.
Immediately pull off pieces to form long pencil-thin ropes. Wroking quickly, cut into 7-inch lengths with a pair of kitchen scissors. Continue pulling until all candy is used or is no longer pliable.
Temper chocolate: Heat 2/3 of chocolate in a heatproof bowl set over a pan of barely simmering water until chocolate registers 118 degrees on a candy thermometer. Remove pan from heat, and add the remaining chocolate; stir with a rubber spatula (avoid using a wooden spoon, which can impart other flavors) until it cools to 84 degrees. Remove any unmelted pieces, and discard. Return bowl to pan, and stir until chocolate reaches 88 to 90 degrees.
Dip top 3 inches of each pepperment stick in the chocolate, if desired. Allow excess to drip off; set on a parchment-lined baking sheet, and let harden. Store in an airtight container at room temperature up to 1 week.
Wear latex gloves to protect your hands from the heat when making peppermint sticks. Work quickly (you might ask someone to help you) since candy will cool and harden fast.Pull pencil-thin pieces from the warm mass of candy, and cut into 7-inch lengths with kitchen.