Table is a List. You can call Table.InsertAt to add rows. Adding columns is a bit more difficult. You will need to do something like:
B4X:
For i = 0 To Table.Size - 1
Dim row() As String = Table.Get(i)
Dim newRow(row.Length + 1) As String
'copy the items from row to newRow and add the new value wherever it needed
newRow(0) = row(0)
'...
Table.Set(i, newRow)
Next