Soak skewers in a shallow pan of water for at least one hour.
Thread skewers with 3 or 4 pieces of marinated pork, alternating with small wedges of lemons and oranges. Place skewers on an area of the grill with no direct flame. Continue to brush marinade during grilling, until meat is browned, about 8 to 10 minutes or to desired doneness.
Serve immediately in pita pockets topped with shredded salad and avocado tzatziki.
Make the marinade by combining the olive oil, juices, chili flakes, chili powder, garlic, salt, and pepper. Cover and refrigerate for at least 30 minutes (although I prefer to marinate for 3 hours or overnight).
Add lemon juice, olive oil, garlic and salt to the yogurt. Add grated cucumber, diced avocado and mix well. Chill for at least one hour. Cat’s Note: To get as much cucumber flavor as possible, grate the cucumber right over the yogurt.