The below code will do this
Imports System.Linq
Namespace ConsoleApplication1
Class Program
Private Shared Sub Main(args As String())
Dim str = GetTenDigitRandomNumbers()
End Sub
Public Shared Function GetTenDigitRandomNumbers() As String
Dim generator As New Random()
Return generator.[Next](0, 1000000).ToString("D10")
End Function
End Class
End Namespace