Julienne the carrot, shred the lettuce and cheese (if needed), slice the avocado, and chop the spinach. Set all aside separately.
Preheat the oven and cook the taco shells according to the directions on the package.
Meanwhile, heat a medium-sized skillet over medium heat; spray with cooking spray, then add the meat and seasonings. Cook until no longer pink, stirring frequently to crumble.
Drain any excess grease from the skillet, then stir in the canned tomatoes; cook for 1-2 minutes longer.
Stuff taco shells with meat and toppings as desired. Serve grapes on the side.