As one of the forum's resident book people, it behooves me to answer this as well as I can:
The name that most immediately leaps to mind is Tiana Highrider (from Andrew Offutt and Richard Lyons's Demon in the Mirror, et al). Red-haired, uninhibited, and she even mentions at one point that her feet are ticklish -- what's not to like?
A few other possibilities: Corson and Nyctasia from J.F. Rivkin's Silverglass and its sequels (which also frequently allude to ticklish fun), C'mell from Cordwainer Smith's "The Ballad of Lost C'mell," Dessylyn from Karl Edward Wagner's "Undertow," and Karamaneh from Sax Rohmer's The Insidious Dr. Fu Manchu et al.
Lester Dent's Pat Savage might be a possibility, but she'd probably break anyone who tried to tickle her in half. So would Peter O'Donnell's Modesty Blaise -- plus O'Donnell frequently mentions that Modesty's feet are rock hard from constantly going barefoot as a child, so any tickler would have to restrict himself to her upper body.