Preheat grill to medium-high heat.
In a large bowl, combine ground lamb, garlic, onion, cumin, chili powder, paprika, garlic powder, oregano, salt and pepper. Mix together until everything is evenly incorporated.
Form the mixture into four equal-sized patties.
Brush each patty with olive oil.
Place patties on the preheated grill and cook for 6 minutes per side, or until desired doneness.
Meanwhile, in a medium bowl, combine yogurt, cilantro, garlic, lime juice, salt and pepper. Mix until everything is evenly incorporated.
When burgers are done, remove from the grill and place on burger buns. Top with tomato slices and lettuce leaves.
Serve burgers with the cilantro-lime sauce on the side. Enjoy!