In a large bowl, mix ground beef or lamb, onion, garlic, parsley, cumin, coriander, salt, and pepper until well combined.
Shape the mixture into oval patties or skewers about the size of an egg.
Preheat your grill or oven to 400°F (200°C). If using wooden skewers, soak them in water for 30 minutes.
Grill koftas for approximately 10-12 minutes per side until browned and cooked through.
For the sauce, whisk together tahini and lemon juice; gradually add water until smooth.
Serve koftas on a platter drizzled with tahini sauce and garnish with parsley.