Combine buttermilk, 1-1/2 teaspoons cumin and 1/8 teaspoon cayenne in heavy-duty plastic food-storage bag; shake gently to blend. Add chicken; seal; toss to coat. Refrigerate at least 1 hour or up to 6 hours.
Combine flour, remaining 1-1/2 teaspoons cumin and 1/8 teaspoon cayenne and the salt on waxed paper.
Drain chicken; blot dry with paper toweling. Coat chicken pieces evenly with flour mixture.
Heat oil in large nonstick skillet over medium-high heat. Working in batches if necessary to avoid crowding skillet, add chicken to hot oil; cook 6 to 8 minutes per batch or until golden and crisp, turning pieces over halfway through cooking. Remove with slotted spoon to paper toweling to drain. Then arrange on platter. Drizzle with lime juice.