Lamb Kabobs with Tzatziki Sauce

• 12 (6-inch) wooden skewers
• 1 1/2 pounds ground lamb
• 2 scallions, finely chopped
• 2 teaspoons onion powder
• 2 teaspoons chopped fresh oregano leaves
• 1 teaspoon chopped fresh rosemary leaves
• 1 teaspoon garlic powder
• 1 teaspoon ground cumin
• 1/2 teaspoon dried thyme
• Salt and freshly ground black pepper
• Oil, for brushing
• 1 bag pita bread, at least 6 loaves
• Tzatziki Sauce, recipe follows

Tzatziki Sauce:

• 2 cups Greek strained yogurt
• 1/2 cucumber, seeded and chopped
• 1 garlic clove
• 2 1/2 teaspoons hot sauce (recommended: Frank's Red Hot)
• 1 teaspoon lemon juice
• Salt and freshly ground black pepper