Martha Rose Shulman of The New York Times offers a healthy meal option with these tacos. Don't worry, they still incorporate cheese:

Vegetables bathed in vinegar are typical condiments in Mexico, but you can bring them to the center of the plate as a filling for a taco. If you want spice, add the chipotle, or garnish with some salsa. If salt is an issue, use ranchero rather than cotija cheese.

See the recipe here