Heat large nonstick skillet over medium heat until hot. Add Ground Beef; cook 8 to 10 minutes, breaking into 1/2-inch crumbles and stirring occasionally. Remove drippings. Stir in 1/4 cup water and 2 teaspoons taco seasoning; cook 3 minutes. Remove from skillet; keep warm.
Combine sweet potatoes, onions, remaining 1/4 cup water and remaining 2 teaspoons taco seasoning in same skillet. Bring water to a boil. Reduce heat; cover and simmer 10 minutes, stirring once. Remove lid; stir in oil; continue cooking, uncovered, 4 to 6 minutes or until potatoes are tender and begin to brown, stirring frequently. Return beef mixture to skillet; continue to cook 2 to 4 minutes or until heated through, stirring occasionally.
Meanwhile, combine yogurt and hot sauce, as desired, in small bowl.
Evenly divide beef mixture into tortillas. Garnish with cilantro and serve with yogurt mixture, as desired.
Nutrition information per serving: 377 Calories; 94.5 kcal Calories from fat; 10.5 g Total Fat; 3.3 g Saturated Fat; 3.3 g Monounsaturated Fat; 76 mg Cholesterol; 174 mg Sodium; 40.2 g Total Carbohydrate; 5.4 g Dietary Fiber; 30.9 g Protein; 4 mg Iron; 7.8 mg Niacin; 0.7 mg Vitamin B6; 2.5 mcg Vitamin B12; 6.9 mg Zinc; 20.1 mcg Selenium; 91.2 mg Choline;