(Photo credit: Kia Caldwell) Piedmont Opera announces that Karen Slack will present “African Queens” to kick off Winston-Salem’s Juneteenth celebration. “African Queens” features works by Jasmine Barnes, Damien Geter, Jessie Montgomery, Fred Onovwerosuoke, Will Liverman, Shawn Okpebholo, Dave Ragland, Carlos Simon, and Joel Thompson, alongside traditional repertoire. Slack performs with pianist Kevin Miller. The program will be offered entirely free {…}