Heat a heavy cast-iron skillet. Add minced beef to the skillet and cook, stirring occasionally until cooked through (5 minutes).
Add chopped onion, garlic and taco seasoning. Saute for a minute until the onion has softened.
Add chopped tomato. Continue to cook on low heat until beef is fully cooked and liquid slightly reduced (7 to 10 minutes).
Towards the end of cooking, add chopped peppers and zucchini. Mix well and cook for 2 minutes. Don't cook the veggies all the way through, it should still have a crunch to it.