For an extra layer of smoky depth, consider using wood chips like mesquite or hickory when grilling the vegetables. If you don't have an outdoor grill, a grill pan on the stovetop or even roasting the vegetables in the oven at 400°F (200°C) will work nicely. Watch carefully to achieve a good char. Adjust the amount of lime juice and salt to your taste. A little bit of heat from a pinch of cayenne pepper or a finely diced jalapeño can also add a welcome kick.