Line a large colander with a cheesecloth. Stir salt into the yogurt, and pour the yogurt into the cheesecloth. Set the colander in the sink or bowl to catch the liquid that drains off. Leave to drain for 24 hours.
After draining for the 24 hours, transfer the resulting cheese to a bowl. Stir in the olive oil. Store in a covered container in the refrigerator.
