In a bowl, mix the vegetable oil, paprika, ground cumin, ground coriander, garlic powder, onion powder, black pepper, salt, and soy sauce (if using).
Place the beef or chicken cubes in the bowl with the marinade.
Toss to coat the meat evenly.
Cover and refrigerate for at least 1 hour, or overnight for best results.
If using wooden skewers, soak them in water for at least 30 minutes to prevent burning.
Thread the marinated meat cubes onto the skewers.
Preheat the grill or a grill pan to medium-high heat.
Place the skewers on the grill and cook for about 8-12 minutes, turning occasionally, until the meat is cooked through and has a nice char.
Enjoy your meal!