In a 12-inch skillet, heat 1 tablespoon of the oil on medium-low heat. Add the chorizo and while occasionally stirring, cook for 7-10 minutes or until its internal temperature is 145°F.
With a slotted spatula, remove the chorizo from the skillet and place in a bowl or on a plate. Leaving the heat on medium low, add the remaining 1 tablespoon of oil and then add the onions and jalapeño. While occasionally stirring, cook until softened and fragrant, about 5 minutes. Add the garlic and cook for 30 more seconds.
Add to the skillet the zucchini, yellow summer squash, cilantro, salt, cumin, oregano, and cayenne. Stir until everything is well combined then cook until the squash is softened and just beginning to release some of its liquid, about 5 minutes. Stir in the corn and cook for another 2 minutes. Taste and adjust seasonings.
To assemble the tacos, place on warm tortillas the cooked chorizo and the squash and corn mixture. Top with avocado slices and queso fresco. Serve with limes and salsa for additional garnishing on the side.
Notes
The chorizo can easily be replaced by beans, bacon, or even eggs if you prefer.