There are many opera theaters in Beijing(https://www.travelchinaguide.com/cityguides/beijing/opera-theaters.htm) , where you can see opera performance every day. You can go to Huguang HUiguan （湖广会馆）or Liyuan Theater. Mei Lanfang Theater has a Beijing Opera show at Christmas night. I suggest you buy ticket at the theater when you just arrive in Beijing, or ask for help with your hotel.