If using wooden skewers, soak them in water for at least 20 minutes to prevent burning on the grill.
In a medium bowl, whisk together the extra virgin olive oil, lemon juice, smoked paprika, garlic powder, sea salt, and black pepper to create the marinade.
Pat the cubed sirloin steak and peeled shrimp dry with paper towels to ensure a good sear.
Add the steak, shrimp, chopped red bell pepper, and red onion to the bowl and toss until everything is thoroughly coated in the spice mixture.
Thread the steak, shrimp, and vegetables onto the skewers, alternating the items to ensure even heat distribution.
Preheat your grill or a heavy-bottomed grill pan over medium-high heat until it is very hot.
Place the skewers on the grill and cook for 3-4 minutes per side, or until the steak reaches your desired doneness and the shrimp are pink and opaque.
Remove the skewers from the heat and let them rest for 2 minutes before serving to allow the juices to redistribute.