Cut chicken breasts in half lenghtwise to make into 4 cutlets. Place into shallow plate or storage container. Set aside.
In a small bowl, whisk olive oil, lime juice, honey, cumin, and chili powder together. Pour over the chicken. Flip chicken around to coat it in the marinade. Cover and refrigerate for 30 mins to 2 hours MAX.
Preheat grill to medium-high heat. Once chicken has marinated, remove from plate and pat dry with paper towels. Discard marinade. Cover both sides of chicken with salt. Place on hot grill for 5 minutes, and then flip to cook for 4 more minutes or until it reaches 160 degrees. Remove from grill and turn grill off.
Split hamburger buns and place 1 tablespoon of ranch dressing on the inside of the top bun. Place one chicken cutlet on the button bun and close bun to make sandwich. Repeat with other cutlets. Serve immediately.