Trim fat from ribs. Place in a large, heavy, deep pot. Add onion, garlic and 1 teaspoon salt. Add enough water to cover ribs, about 10 to 12 cups.
Bring to a boil over medium-high heat. Reduce heat to maintain a simmer and cook, uncovered, for 1 hour. Cover pot; cook for 30 minutes.
Remove pot from heat and drain. Transfer ribs to cutting board and let stand until cool enough to handle.
In same large pot as before, place corn, tomatoes, chiles, barbecue sauce, pepper and remaining 1/2 teaspoon salt. Remove and discard any fat and bones; shred remaining meat. Add meat and 1/4 cup water to pot. Bring to a simmer and cook until heated through, about 5 minutes. Serve. Or keep mixture covered with plastic wrap in the refrigerator for several days and use as needed. Or freeze for up to 3 months. Makes 8 cups.
Heat corn tortillas in microwave for 15 to 45 seconds. Meanwhile, heat 1/4 cup shredded pork for each tortilla until warmed through. Top each tortilla with filling. Mixture could also be served with rice or on small potato rolls.
Nutrient Value Per Taco: 255 calories, 8 g fat (3 g saturated),15 g protein, 30 g carbohydrate, 2 g fiber, 779 mg sodium, 44 mg cholesterol.