To make the mint relish, mix together all the ingredients in a bowl, cover and chill until needed.
Put the beef, red onion, garlic, red chilli and herbs in a food processor or blender. Add the ground ginger, chilli powder, cumin, coriander seeds and egg. Season well, then process until fairly smooth and well combined.
Divide the mixture into 16 balls. Roll each ball in the breadcrumbs, place on a baking sheet and drizzle with the oil. Place in a preheated oven, 200°C (400°F), Gas Mark 6, for 15–20 minutes or until cooked through.
Serve the beef koftas on cocktail sticks with the mint relish and lime wedges to squeeze over.