Trim fat from meat. Cut meat into 6 pieces. In a 3-1/2- or 4-quart slow cooker place meat, undrained tomatoes, onion, chipotle peppers, oregano, cumin, and garlic.
Cover and cook on low-heat setting for 8 to 10 hours or on high-heat setting for 4 to 5 hours. Remove meat from cooker. Using 2 forks, pull meat apart into shreds. Place meat in a large bowl. Stir in enough cooking liquid to reach desired consistency. Divide meat among warm tortillas, spooning it just below the centers. Top with cheese, Pico de Gallo Salsa, and, if desired, jicama and sour cream. Roll up tortillas. Makes 6 servings.
Pico de Gallo Salsa
In a medium bowl combine tomatoes; onion; cilantro; serrano chile pepper, and dash sugar. Cover; chill several hours.