In a large bowl mix together paprika, Mexican chilli powder, oil, brown sugar & lime or lemon rind. Add meat and turn over so coated. Cover bowl with plastic wrap & refrigerate for 1 hour or overnight. Heat a dash of oil in a heavy-based frying or grill pan. Add steak to the hot pan & cook 3-4 minutes each side. Remove from pan & allow to rest while finishing the salad. Add peppers to pan & cook only until lightly grilled, then set aside. Mix lettuce, ½ cup mint leaves & peppers, then arrange avocados, mango & beef slices on top & finish by drizzling dressing. Serve warm.
Dressing
In a blender mix together plain yoghurt, 2 Tbsp oil, 8-10 mint leaves, green chilli, deseeded and sliced. Blend until smooth.