Heat the pan: Set a large skillet over medium-high heat and add olive oil. Let it shimmer.
Sauté aromatics: Add diced onion and bell pepper.
Cook 3 to 4 minutes until slightly softened and fragrant.
Add zucchini and corn: Stir in zucchini and corn. Cook another 3 to 4 minutes. You want light browning for flavor.
Stir in garlic and spices: Add garlic, chili powder, smoked paprika, and cumin.
Cook 30 seconds, stirring, until the spices smell toasty.
Add the beef: Toss in the leftover ground beef. Break up any clumps and warm through for 2 to 3 minutes. Season with salt and pepper.
Finish with tomatoes: Add the halved tomatoes and cook 1 to 2 minutes, just until they start to soften.
Brighten it up: Turn off the heat.
Add lime zest and juice. Fold in chopped herbs. Taste and adjust seasoning.
Serve your way: Spoon into bowls over rice or quinoa, tuck into tortillas, or pile onto greens.
Add beans, cheese, avocado, or a fried egg if you like.