For the herb butter: Combine the garlic, lemon zest and juice, parsley, butter and a pinch of salt in a small bowl. Keep at room temperature for topping the steak before serving.
For the salad: Prepare an outdoor grill over medium-high heat. Grill the corn until well-marked, turning as needed, about 5 minutes. Let cool for a few minutes then slice the kernels off and transfer to a medium bowl. Add the oregano leaves, tomato, onion, zucchini, Fresno chile, feta, olive oil, vinegar and salt to taste. Toss to coat evenly.
For the surf and turf: Toss the prawns with the garlic, lemon juice and olive oil in another medium bowl and let marinade while grilling the steaks. Massage the strip steaks with olive oil and sprinkle each side with salt. Grill the steaks until well-marked and medium-rare, about 3 minutes per side. Let the steaks rest and grill the prawns until pink and cooked through, about 3 minutes per side. Divide the steaks, prawns and salad between 2 plates. Top the steaks with a spoonful of the herb butter.