Cook ground round in a large Dutch oven over medium heat until the meat is browned, stirring to crumble. Drain well, and return meat to pan. Stir in water, stewed tomatoes, and soup mix, and bring to a boil. Reduce heat, and sim-mer, uncovered, 10 minutes, stirring occasionally. Stir in ditalini and chopped spinach, and simmer for 7 minutes or until the pasta is tender.