Preheat grill to 400 degrees. Clean the grates once it has heated.
In a bowl, whisk together the sour cream or crema, mayonnaise, cilantro, garlic, chipotle pepper, lime zest and lime juice. Taste and season the mixture with salt if needed. Set aside.
Place the husked corn directly onto grill grates. Grill the corn for about 3 minutes or until kernels begin to turn golden brown and look charred. Turn over and repeat. When all sides are browned, remove from the grill.
With a brush or a spoon, coat each ear of corn with the crema mixture. Sprinkle with crumbled cojita cheese and any additional chipotle pepper, if desired. Serve immediately with extra lime wedges.