Mix in a bowl ground beef, rice, egg, marinara sauce, salt, pepper, garlic powder, paprika, adobo seasoning, and cumin. With clean hands, incorporate everything together. Shape into meatballs and set aside.
Add tomatoes, onion, marinara sauce, garlic powder, adobo, and water to a blender. Blend until smooth.
For the full step-by-step instructions and video tutorial, download the Little Lunches app.