Make Tortillas - Heat oven to 225°F (105°C). Lightly dampen a kitchen towel. On a hot griddle or heavy skillet, warm homemade or store bought tortillas on both sides until hot and blistered. Transfer to the towel and wrap. When all 12-14 tortillas are done, place wrapped towel in oven to keep warm.
Cook Pineapple - Combine sugar and pineapple chunks in a nonstick skillet over medium heat. Stir often until the sugar is melted and the pineapple is caramelized, about 5 minutes. Place in a serving bowl and cover.
Cook Meat - Bring meat to room temperature. Heat a large, heavy skillet over high heat. Drain off excess liquid from meat and blot dry between layers of paper towels. Add oil to hot skillet and swirl to coat. Add 2 tbsp of reserved marinade. Add meat in a single layer. Let meat cook undisturbed over high heat until browned on the bottom. Stir and continue to cook until cooked through but still moist, about 5 minutes total. After about 3 minutes, stir in a 1-2 tbsp of reserved marinade if meat seems too dry. Transfer to a serving bowl.
Serve - Place covered tortillas in a basket and bring out along with bowls of hot meat, pineapple, salsa, chopped onion, cilantro, lime wedges, and hot sauce. Let diners assemble their own tacos with meat, pineapple, and whatever toppings they'd like.