Combine the oregano, olive oil and lemon rind in a bowl with a pinch of salt and pepper, and rub the mixture all over the lamb steaks. Arrange on a foil-lined grill rack and slide under a preheated hot grill for 6–8 minutes, turning once, until cooked to your liking.
Meanwhile, cook the kale in a large pan of salted boiling water for 5–6 minutes, until tender.
Combine the salsa ingredients in a bowl and season to taste.
Heap the kale on to serving plates, then arrange the lamb on top and serve with the salsa.