Registering endpoints and HTTP method for exemption of authentication
Basically what you are asking is what can we do about this


    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep1, method.GET))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep1, method.POST))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep1, method.PUT))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep1, method.DELETE))

    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep2, method.GET))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep2, method.POST))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep2, method.PUT))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep2, method.DELETE))



and the contents of the else block as well.

I would create a method that takes the Endpoints ep1 and ep2 as parameters

something like 

Public Sub MethodAddingEndpointsToExemptedList(endpoint As String)
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(endpoint, method.GET))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(endpoint, method.POST))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(endpoint, method.PUT))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(endpoint, method.DELETE))
End Sub


and then you can just call this method inside the if block like this

If allMethods Then
    MethodAddingEndpointsToExemptedList(ep1)
    MethodAddingEndpointsToExemptedList(ep2)
Else
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep1, method))
    _ExemptEndpoints.Add(Tuple.[New](Of String, Method)(ep2, method))
End If


You could go a step further and create a list of the endpoints and then use a foreach loop to add them to the list of Exempted endpoints.