To make the Tzatziki:
In a medium bowl, combine cucumber, yogurt, lemon juice, mint and garlic, season with salt and pepper. Cover, and refrigerate until ready to use.
To make the patties:
In a medium bowl, gently combine lamb, garlic salt, pepper, coriander and cumin. Form into 8 patties, each about 1/2 inch thick. Grill until done the way you like. Serves 8.