Meanwhile, rub each ear of corn generously with olive oil and season with salt and pepper. When the grill pan is hot, add corn and cook until charred on all sides, about 4 minutes per side. Set aside.
Re-heat another few T of oil in the same grill pan or cast iron skillet. When oil is hot, add chicken and cook for 7-8 minutes per side, until cooked through and juices run clear. Wrap the cooked chicken breasts tightly in foil while you finish preparing the corn salsa.
Cut the charred corn off the cob and add to the bowl of onions and lime juice. Stir in cilantro, garlic, jalapeños, a tsp of olive oil, and season with salt and pepper to taste.
Add 2 c arugula to each plate, followed by sliced chicken breast, topped with charred corn salsa.