Add the ground beef and onion to a dutch oven or large pot over medium-high heat. Cook the beef, while breaking it up, until no longer pink, about 5 minutes.
Add the paprika, cumin, garlic, ginger, cinnamon, cayenne, 2 tsp salt, and 1/2 tsp black pepper to the pot and cook while stirring for about 1 minute.
Add the carrots, celery, tomatoes, and lentils and cook while stirring for about 1 minute.
Stir in the water and bring to a boil.
Reduce the heat to medium-low and simmer the soup, stirring occasionally, until lentils are tender, about 30 minutes.
Season the soup with additional salt & pepper to taste.