public void Delete( 
   MapMember mapMember,
   long oid
)

var deleteFeatures = new EditOperation();
deleteFeatures.Name = "Delete Features";
var table = MapView.Active.Map.StandaloneTables[0];
//Delete a row in a standalone table
deleteFeatures.Delete(table, oid);

//Delete all the selected features in the active view
//Select using a polygon (for example)
//at 2.x - var selection = MapView.Active.SelectFeatures(polygon).Select(
//      k => new KeyValuePair<MapMember, List<long>>(k.Key as MapMember, k.Value));
//deleteFeatures.Delete(selection);
var selection = MapView.Active.SelectFeatures(polygon);
deleteFeatures.Delete(selection);

//Execute to execute the operation
//Must be called within QueuedTask.Run
deleteFeatures.Execute();

//or use async flavor
//await deleteFeatures.ExecuteAsync();

//must support editing!
//var featSceneLayer = .... ;
if (!featSceneLayer.HasAssociatedFeatureService || 
    !featSceneLayer.IsEditable)
  return;

var delOp = new EditOperation()
{
  Name = "Delete selected features"
};
//Assuming we have a selection on the layer...
delOp.Delete(featSceneLayer, featSceneLayer.GetSelection().GetObjectIDs());
await delOp.ExecuteAsync();//await if needed but not required