You are looking for the cheapest solution to Hong Kong then have a look on this deal based on Air China (Star Alliance) when flying from Switzerland (Geneva). Return flights with a layover in Beijing are available already for €274. (Incl. checked bag). Limited availability in spring 2018 so hurry up with booking if this is a deal you have been waiting for..
You can book your hotel room in Hong Kong through Booking.com or Hotels.com. Air China sale is available till 31st of March. Travel dates 30th of April to 11th of June 2018. Based on latest date of your outbound flight from Europe. Max stay 3 months.
Booking samples
Geneva - Hong Kong from €274
Zurich - Hong Kong from €368
Paris - Hong Kong from €346
Vienna - Hong Kong from €352
Europe - Macau from €348
Germany - Taipei from €363
Amsterdam - Taipei from €348
Booking sample of cheap return flights from Switzerland to Hong Kong from €274 here. You would fly from Switzerland to Hong Kong on Sunday, 21st of January. Your return flight from Asia to Europe woudl be then on 29th of January 2018.