Whisk together vegetable oil, kosher salt, chili powder, paprika, cumin, cayenne pepper, minced garlic, brown sugar, and chipotle in adobo sauce.
In a gallon-sized bag, combine marinade and chicken and refrigerate for 30-60 minutes.
Once ready to grill, thread the chicken on skewers. Place them on the grill, turning once or twice until sides are cooked and insides are no longer pink.
Place on a plate and sprinkle with fresh cilantro if desired.
In a food processor, combine avocado, Greek yogurt, garlic, lime juice, and cilantro. Pulse until smooth. Add salt and pepper to taste and serve with chicken.
