01 - In a medium saucepan, bring water and salt to a boil. Stir in rice, reduce heat to low, cover, and cook for 15 minutes or until water is absorbed and rice is tender. Fluff with a fork and set aside.
02 - Heat olive oil in a large skillet over medium heat. Add onion and garlic; sauté for 2-3 minutes until softened. Add ground beef, breaking it up, and cook until browned, about 5-6 minutes. Drain excess fat if needed. Stir in chili powder, cumin, paprika, oregano, salt, and pepper. Add tomato sauce and water; simmer for 3-4 minutes until slightly thickened.
03 - Combine black beans, cumin, chili powder, and salt in a small saucepan. Heat over medium heat until warmed through, about 3-4 minutes, stirring occasionally.
04 - Warm tortillas in a dry skillet over medium heat for 20-30 seconds per side or microwave covered with a damp towel for 30 seconds.
05 - Lay each tortilla flat. Spoon approximately 1/4 cup rice, 1/4 cup beans, and 1/4 of the beef mixture down the center. Top with cheese, lettuce, tomato, sour cream, and cilantro if desired.
06 - Fold in the sides and roll the tortilla tightly. Serve immediately.