In a bowl, mix together ground meat, grated onion, garlic, parsley, cilantro, cumin, coriander, paprika, salt, and pepper. Form into small meatballs (kefta).
Heat olive oil in a tagine or large skillet. Brown the meatballs on all sides.
Add tomato slices, olives, and preserved lemon (if using). Cover and simmer until meatballs are cooked through.
Garnish with additional fresh herbs before serving.