Heat a nonstick pan, grill pan, or outdoor grill over medium-high heat. Coat the grill grates or pan with about a teaspoon of oil so that the chicken doesn’t stick. Pat the chicken dry with paper towels, rub with olive oil on all sides, and season with salt and pepper to taste. Sear or grill the chicken on each side until golden, crispy, and cooked through (about 5 minutes per side for small, thin chicken breast halves, up to 10-12 minutes per side for larger, thick chicken breasts, or about 6-7 minutes for chicken thighs). The meat is done when it reaches an internal temperature of 165°F. Allow the meat to rest for about 5 minutes before slicing and using in the sandwiches.