Pierce sweet potatoes with fork several times. Microwave on HIGH 3 minutes. Turn potatoes. Microwave again on HIGH 2 to 3 minutes or until potatoes are fork-tender but still firm. Let stand until cool enough to handle. Peel potatoes and cut into 1-inch chunks. Set aside.
Precooking the sweet potatoes before grilling helps reduce overall grill time and allows for even cooking when incorporated with the other vegetables.
Toss tomatoes, squash, zucchini, 1 tablespoon of the oil, paprika, garlic salt and pepper in medium bowl until well coated. Set aside.
Place large cast iron skillet on preheated grill over medium-high heat (375°F to 400°F). Heat remaining 2 tablespoons oil in cast iron skillet. Add potatoes; cook 4 to 5 minutes or until lightly charred and tender, stirring after each minute. Push potatoes around edges of pan.
Place chorizo and onion in center of pan. Cook and stir 3 to 4 minutes or until lightly charred. Push chorizo mixture around edges of pan. Add squash mixture to center of pan. Cover pan or close grill. Cook 4 to 5 minutes or until squash is tender and tomatoes begin to burst, stirring after each minute. Gently stir in water and vinegar until blended.
Spanish chorizo is a hard, cooked & cured pork sausage. It can be found in Latin markets, butcher shops, some supermarkets, or ordered at online specialty stores. Pepperoni or salami may be substituted for Spanish chorizo.