In a small bowl, stir together olive oil, chipotle peppers, adobo sauce, lime juice, minced garlic, and salt, and pepper.
Place steak in a large ziplock bag and pour marinade over it. Let air out of bag before sealing and massaging marinade into steak a bit. Place in fridge for 3-6 hours.
Thread marinated meat onto skewers, alternating with peach wedges and pieces of red onion (If you're using wooden skewers, be sure to soak them in water for a bit before threading). Lightly brush peaches and onion with olive oil.
Heat grill to medium-high and lightly brush grates with olive oil. Place skewers on grill and cook for about 8-10 minutes, turning often, until steak is cooked to your liking (I like medium rare, which should register at 130-135 on a meat thermometer). Let rest for a few minutes before serving.