Cook brown rice according to package directions, omitting salt and fat; drain well.
While rice cooks, heat a large nonstick skillet over medium-high heat. Add beef; cook 5 minutes or until browned, stirring to crumble. (Drain if necessary, and return beef to pan.) Stir in beans and next 4 ingredients, and bring to a boil. Cover, reduce heat, and simmer 12 minutes or until slightly thick, stirring occasionally.
Serve beef mixture over rice, and top with sour cream and cilantro.