Special equipment: food processor
Preheat grill to high. Soak skewers in water for 25 to 30 minutes.
In a large bowl combine lamb, scallions, onion powder, oregano, rosemary, garlic powder, cumin, thyme, salt and pepper, to taste. Form meat around skewers, making an oblong sausage shape pressing and securing firmly. Refrigerate 30 minutes. Remove skewers from refrigerator. Brush grill with oil. Grill kabobs until charred on the outside and medium-rare on the inside, turning only once, about 3 minutes each side. Brush pita lightly with oil, and grill briefly on both sides to warm. Remove lamb kabobs from skewers and place 2 on each pita. Drizzle with Tzatziki Sauce to serve.
Add the yogurt, cucumber, garlic, hot sauce, lemon juice and zest in a food processor and blend until smooth. Season with salt and pepper, and transfer to a bowl. Refrigerate at least 1 hour before serving.