1 boneless leg of lamb or lamb shoulder (3 to 4 pounds)
1/2 cup canola oil
1/2 cup lemon juice
1/3 cup soy sauce
1/3 cup packed brown sugar
1/4 cup vinegar
3 tablespoons Worcestershire sauce
1 tablespoon ground mustard
1/2 teaspoon pepper
1 large green pepper, sliced
1 large sweet red pepper, sliced
1 large onion, sliced
16 flour tortillas (7 inches), warmed
Chopped tomato and cucumber, optional
Cut lamb into thin bite-size strips. In a large resealable plastic bag, combine the oil, lemon juice, soy sauce, sugar, vinegar, Worcestershire, mustard and pepper; add lamb. Seal bag and turn to coat; refrigerate for 3 hours, turning occasionally.
Transfer lamb and marinade to a Dutch oven or large saucepan; bring to a boil. Reduce heat; cover and simmer for 8-10 minutes or until meat is tender. Add peppers and onion; cook 4 minutes longer or until vegetables are crisp-tender.
Using a slotted spoon, place meat and vegetables on tortillas; top with tomato and cucumber if desired. Fold in sides of tortilla.