01 - Bring water and salt to boil in a medium saucepan. Stir in rice, reduce heat to low, cover, and simmer for 15 minutes 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. Sauté onion and garlic for 2-3 minutes until softened. Add ground beef and cook 5-6 minutes until browned, breaking it up as it cooks. Drain excess fat if necessary. Stir in chili powder, cumin, smoked 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 for 3-4 minutes, stirring occasionally, until warmed through.
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 of rice, 1/4 cup of beans, and 1/4 of the beef mixture down the center. Top with shredded cheese, lettuce, diced tomato, sour cream, and optional cilantro.
06 - Fold in the sides of the tortilla and roll up tightly. Serve immediately.