Add cubed pork tenderloin, lemon juice, olive oil, garlic, dried oregano, onion powder, salt, and pepper to a large bowl and massage to coat pork thoroughly. Set aside to marinate for ten minutes.
Heat olive oil in a skillet over medium-high. Transfer marinated pork to hot skillet and cook for 10-15 minutes, flipping periodically, until cooked through.
Serve with warm Greek pitas, red onions, chopped tomatoes, and Tzatziki (see recipe).
