Combine salsa ingredients in a bowl, season, and set aside.
Soak onion rings in milk and sift flour, cornflour, and paprika into a separate bowl.
Heat 1cm of vegetable oil in a heavy-based frying pan until sizzling.
Dredge soaked onions in the flour mixture and fry in batches for 2 minutes until golden.
Drain fried onion rings on kitchen paper and sprinkle with sea salt.
Rub steaks with oil, season, and sear in a hot pan for 3 minutes per side.
Rest the steaks for 3 minutes after cooking.
Toss salad leaves with olive oil and lime juice.
Plate the steaks with onion rings, topped with chimichurri and salad on the side.