Heat olive oil in a large skillet over medium heat.
Add diced onion and minced garlic to the skillet and sauté for 2-3 minutes until fragrant and translucent.
Add ground beef to the skillet and cook, breaking it apart with a spatula, until browned and cooked through, about 6-8 minutes.
Drain excess fat from the skillet if necessary.
Add diced red bell pepper, green bell pepper, and zucchini to the skillet. Cook for 5 minutes, stirring occasionally, until vegetables are tender.
Stir in smoked paprika, ground cumin, chili powder, black pepper, and salt. Mix well to combine all flavors.
Add chopped spinach and cook for an additional 1-2 minutes until wilted.
Sprinkle shredded cheddar cheese evenly over the skillet. Cover and cook for 1-2 minutes until cheese is melted.
Remove from heat and serve immediately.