In a large bowl, combine the vegetable oil, soy sauce, tomato paste, paprika, cumin, coriander, garlic powder, onion powder, cayenne pepper, salt, and black pepper.
Add the meat cubes to the marinade and mix well to coat all pieces evenly. Cover and refrigerate for at least 2 hours or overnight for better flavor.
Preheat your grill or grill pan to medium-high heat.
Thread the marinated meat onto the soaked bamboo skewers, alternating with onion and bell pepper chunks.
Place the skewers on the grill and cook, turning occasionally, until the meat is cooked through and has a nice char, about 8-10 minutes depending on the size of the meat cubes.
Remove the brochettes from the grill and let them rest for a few minutes before serving.
Enjoy your meal!