Getting property values from dynamic

I use Dapper with dynamics because the table to be queries is not known until runtime, so POCO classes aren't possible.

I am returning Dapper's results via WebAPI. To save bandwidth, I need to return just the values from Dapper, not the property names, e.g.:

{
    7,"2013-10-01T00:00:00",0,"AC",null,"ABC","SOMESTAGE"
},...

And not:

{
TID: 7,
CHANGE_DT: "2013-10-01T00:00:00",
EFFECTIVE_APPTRANS: 0,
EFFECTIVE_APPTRANS_STATUS: "AC",
DEVICE: null,
PROCESS: "ABC",
STAGE: "SOMESTAGE"
},...

I'm having some trouble figuring out a reasonable way to do this. I've tried abusing Dapper's mapping feature:

var tableData = Database.Query<dynamic, dynamic, dynamic>(connectInfo, someResource.sql,
    (x, y) =>
    {
        List<object> l = new List<object>();
        object o = x;

        foreach(var propertyName in o.GetType().GetProperties().Select(p => p.Name)) {
            object value = o.GetType().GetProperty(propertyName).GetValue(o, null);
            l.Add(value);
        }
        return l as dynamic;
    },
    new {implantId, pendingApptrans},
    splitOn: "the_last_column");

I've also tried having Dapper return a List using the same base code.

The idea was that I'd extract property values within the map function because it allows me to play with rows before anything is returned, but I get empty results without error:

[
    [ ], [ ], [ ], [ ], [ ], [ ], [ ]
]

Additionally, I don't know any column names to split on, which the mapping feature wants. However even when I enter the last column name from a test query, the results are the same.

How can I return only values from Dapper's dynamic return value? Do I need to resort to post-processing the dynamic after the Dapper call?