For the Pork Belly : Preheat the oven to 150°C. Pat the pork belly dry and rub with salt, pepper, garlic powder, onion powder, smoked paprika, lime juice, and oil. Place it skin-side up on a tray and roast for 2 hours until tender. Increase heat to 240°C and roast for an additional 20 minutes to crisp the skin. Rest the pork belly for 10 minutes before slicing into small cubes.
For the Salsa Roja : Add dried chilies, tomato, garlic, and onion to a pot with water. Simmer for 10 minutes until softened. Transfer everything to a blender with salt and vinegar. Blend until smooth. Optional: Strain for a smoother consistency.
Assembling the Tacos : Warm tortillas over a dry skillet. Add crispy pork belly pieces. Spoon salsa roja on top. Add onions, cilantro, and optional toppings. Serve immediately with lime wedges.