Put the minced beef in a mixing bowl with the paprika, garlic granules, salt and pepper. Mix well, then divide into 4 equal-sized balls.
Heat the oil in a frying pan over a medium-high heat. Add a beef ball to the pan, then press a tortilla directly on top. Use a spatula to smash it down flat so the beef spreads under the tortilla.
Cook until the beef is crispy and browned. Flip and cook for another 1 to 2 minutes to toast the tortilla. Repeat for the rest.
While the tacos are cooking, mix the yoghurt sauce ingredients together in a bowl.
Spread some yoghurt sauce over the beef side of each taco, then top with sweetcorn, tomato, onion, avocado, lettuce, feta and coriander. Finish with a squeeze of lime and serve.