I think it is relatively easy to find anything zero waste in Vienna. Now you can get more and more packaging-free produce in grocery stores and you can ask at the counter to put the sliced cheese or salami in your own container. (I am not sure how it is right at the moment during COVID19.) Here is a quick list of Bulk stores and markets in Vienna:
Bulk Stores:
Waste-Less.at waste-less.at obviously :D Zero waste Grocery stores: Lieber Ohne https://lieberohne.at Otto-Bauer-Gasse 10, 1060 Wien Tel: 0043 1 375 0064 Opening hours: Mo-Fr 9:00-19:00 Der Greißler https://www.der-greissler.at Albertgasse 19, 1080 Wien Tel: 0043 677 6161 5420 Opening hours: Mo-Fr 9:30-21:30 h Sa 8:00-18:00 Lunzers Maßgreißlerei http://mass-greisslerei.at Heinestraße 35, 1020 Wien Tel: 0043 1 212 1387 Opening hours: Mo-Fr 9:00-19:00 h Sa 9:00-17:00 Uhr Warenhandlung Wenighofer https://www.warenhandlung.at/ Maxergasse 13, 1030 Wien Tel: 0043 1 286 4095 Opening hours: Mo-Fr 7:30-18:00 Sa 8:00-13:00
Markets: