In a small bowl, combine smoked paprika, brown sugar, salt, 1 teaspoon dry mustard, 1 teaspoon garlic powder, chili powder and black pepper. Sprinkle and pat mixture evenly on both sides of chicken thighs. Chill, covered, for 30 minutes.
Meanwhile, in a small saucepan, combine ketchup, maple syrup, molasses, chipotle peppers, Worcestershire sauce and the remaining 1 teaspoon dry mustard and ½ teaspoon garlic powder. Bring just to boiling; reduce heat to low, and simmer uncovered for 15 minutes, stirring occasionally. Set aside.
Prepare a gas or charcoal grill for direct cooking over medium-high heat. Arrange chicken on a lightly oiled grill rack, cover grill, and cook 4 minutes. Flip and cook 4 minutes more. Stir lime juice into sauce. Brush chicken with some of the sauce, flip and cook 1 minute. Brush sauce on the second side, flip and cook 1 minute more, or until done (170뿯½). Remove from grill; let rest 5 minutes. Serve with lime wedges for squeezing, if desired.
