SKOKIE, IL—Amanda Wyner, 23, who in 1998 spent a week vacationing at a Kenya resort during college spring break, strode confidently Monday into Harambe, a Woodfield Mall store specializing in African art and collectibles. "This is a tribal mask," Wyner stated authoritatively to her sister while holding an Ashanti war mask. "The Africans wear these during actual ceremonies."