Heat the avocado oil in a large cast-iron skillet over medium-high heat until shimmering.
Add the ground beef to the skillet, breaking it into small crumbles with a wooden spoon, and cook until browned and fully cooked through.
Add the diced yellow onion, chopped zucchini, and diced red bell pepper to the skillet with the beef.
Sauté the mixture for 5 to 7 minutes, stirring occasionally, until the vegetables are tender but still retain a slight crunch.
Stir in the minced garlic, smoked paprika, sea salt, and black pepper, cooking for 1 minute until the spices become fragrant.
Pour the coconut aminos over the mixture and toss well to ensure every ingredient is glazed and flavorful.
Add the baby spinach to the skillet and fold it into the beef and vegetables just until it begins to wilt.
Remove from heat and serve immediately in a bowl for a clean and nutrient-dense meal.