In a large pot or Dutch oven, heat the vegetable oil over medium-high heat.
Add the chopped onion, garlic, and bell pepper. Sauté until the vegetables are softened, about 5 minutes.
Add the chopped tomatoes and tomato paste. Stir well to combine.
Add the pork shoulder or pork loin to the pot and brown on all sides.
Stir in the ground cumin, paprika, oregano, black pepper, and salt.
Add the chicken broth, soy sauce, and Worcestershire sauce. Bring to a boil.
Reduce heat to low, cover, and simmer for 1.5 to 2 hours, or until the pork is tender and can be easily shredded with a fork.
Remove the pork from the pot and shred it using two forks. Return the shredded pork to the pot and mix well with the sauce.
In a small bowl, mix together the mayonnaise, mustard, ketchup, and hot sauce (if using). Set aside.
Slice the French rolls or bolillos in half lengthwise.
Spread a generous amount of the sauce on both halves of each roll.
Fill each roll with a generous portion of the shredded pork.
Top the pork with sliced cucumber, shredded cabbage, grated carrots, chopped cilantro, pickled jalapeños (if using), and sliced tomatoes.
Enjoy your meal!