Combine chipotle pepper and sour cream in a small bowl; set aside. Combine tomato and salt in a medium bowl; set aside.
Sprinkle both sides of chicken with cumin and black pepper. Place a large nonstick skillet over high heat until hot; coat with cooking spray. Add chicken, and cook 1 minute on each side. Reduce heat to medium, and cook 3 to 4 minutes on each side or until done. Remove from skillet, and let stand 5 minutes.
Slice chicken diagonally across grain into thin strips. Wrap tortillas in wax paper or damp paper towels, and microwave at HIGH 20 seconds or until warm.
Spoon 2 tablespoons sour cream mixture down the center of each tortilla; top each with a lettuce leaf. Divide chicken evenly over lettuce; sprinkle with tomato. Squeeze lime over tomato, if desired. Roll up, and slice in half crosswise, securing each half with a wooden pick.