1. Place first 11 ingredients in a 3- to 4-quart electric slow cooker; stir well. Cover and cook on LOW for 4 hours or until barley is tender and liquid is absorbed. Stir in 1/4 cup cilantro.
2. Heat tortillas according to package directions. Spoon 2/3 cup barley mixture down center of each tortilla. Sprinkle each with 1 1/2 tablespoons cheese; roll up. Place 1 cup lettuce on each of 8 plates; top each with 1 burrito. Spoon 1 tablespoon salsa and 1 tablespoon sour cream over each serving. Sprinkle with additional cilantro, if desired.