1. Remove the steak from the fridge about 20 minutes before grilling. Meanwhile, combine salt, brown sugar, smoked paprika, thyme, black pepper, garlic powder, onion powder, mustard and cumin in a small bowl. Drizzle steak with olive oil and season with a few teaspoons of spice rub; set aside. Preheat grill to medium-high. Grill steak for seven minutes on each side. Let rest 10 minutes before slicing.
2. To assemble salad, gently toss lettuce, cucumber, tomatoes, shaved corn kernels and peaches. Top with fresh mint and sliced steak. Mix dressing ingredients until combined, then drizzle over salad and toss to coat.