Heat oil in a frying pan over medium-high. Add chili powder, cumin, coriander and cinnamon, and sauté spices for 1 min. Add beef, oregano, Worcestershire and salt, stir gently to combine, and simmer for 6 min or until flavourful.
Combine sour cream, lime juice, sugar and salt. Set aside.
Working in batches, heat tortillas in a dry skillet and wrap in a clean kitchen towel to keep them warm.
Serve braised beef with sour cream sauce, tortillas, arugula, avocado and feta.