public void Delete( 
   MapMember mapMember,
   long oid
)

var deleteFeatures = new EditOperation() { 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
if (!deleteFeatures.IsEmpty)
{
  var result = deleteFeatures.Execute(); //Execute and ExecuteAsync will return true if the operation was successful and false if not
}

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