Whisk together first 6 ingredients in a large bowl until smooth. Add tuna and next 5 ingredients; toss gently to combine.
Line each pita half with lettuce, and fill evenly with salad. Serve immediately.
Wine note: "Tahini pairs well with Hangtime Pinot Noir 2003 [$16]. Pinot Noir always turns sweeter with foods that are salty. This great pick is fruity, with flavors of cherry and strawberry." --Rosalind Johnson, Divas Uncorked, Massachusetts