You need to put a bone where you want the effect to appear.
Then use.
Spine.Bone bone = skeletonAnimation.Skeleton.FindBone("your effect bone");
Vector3 worldPosition = bone.GetWorldPosition(skeletonAnimation.transform);
It's ideal if this script runs after SkeletonAnimation.Update. Otherwise, there can be a slight offset (your position may come from the previous frame). But if the bone never moves, this should be safe either way.