Stir the ground pepper, chipotle powder, and salt in a small bowl, then rub it all over each chicken thigh. Heat a grill pan over medium-high heat, then coat with cooking spray. Grill the chicken thighs until done, about 5 minutes on each side. Remove from the pan and allow to cool for about 2 minutes, then shred the meat.
Mango Salsa
In a medium bowl, stir together the mango chunks, avocado chunks, diced red onion, and cilantro. Seed the grilled jalapeño, then mince the skin and toss with the other salsa ingredients. Sprinkle the juice of the limes over the salsa and toss.
Slaw
Whisk together the olive oil, apple cider vinegar, lime juice, hot sauce, and salt. In a serving bowl, toss the vinaigrette with the cabbage, bell pepper, carrots, and red onion.
Mound the chicken on each of the slider bun bottoms, add some salsa, then the bun tops. Serve with the slaw on the side.