In a medium saucepan, heat sugar, butter, corn syrup, and a pinch of salt over medium, stirring, until sugar has dissolved, about 7 minutes.
Remove pan from heat; stir in orange zest, pecans, and flour. Transfer to a bowl; cover with plastic wrap, and refrigerate until dough is firm, about 2 hours.
Preheat oven to 350 degrees. Line two large baking sheets with parchment. Drop dough by teaspoons, about 2 inches apart, onto sheets (6 per sheet); roll into balls.
Bake until cookies are golden brown (they will harden as they cool), 9 to 10 minutes. Transfer cookies on parchment to a wire rack. Repeat with remaining dough. Let cookies cool completely.
This dough needs to chill for a couple of hours before baking, but you can also leave it in the fridge for up to 2 weeks and bake when you like.