In a medium mixing bowl, whisk together peanut butter, soy sauce, honey, rice vinegar or lime juice, sesame oil, grated ginger, minced garlic, chili flakes, and water or broth until smooth and well combined. If using coconut milk, add it now and whisk until the sauce is creamy and pourable with no lumps remaining.

Place chicken pieces in the bottom of your slow cooker in a single layer if possible. Pour the prepared peanut sauce over the chicken. Use a spoon to ensure every piece is coated, tucking sauce around all sides so nothing is left exposed.

Cover and cook on low for 5 to 6 hours or on high for 2.5 to 3.5 hours. The chicken is done when it reaches an internal temperature of 165°F and shreds easily with a fork. The meat should pull apart without resistance and appear opaque throughout.

Once cooked, use two forks to shred the chicken directly in the slow cooker, pulling it into bite-sized pieces. Stir everything together so the shredded chicken absorbs the rich peanut sauce. Let it rest uncovered for 5 minutes - the sauce will naturally thicken as it cools slightly.

Serve hot over your choice of rice or noodles. Top generously with crushed peanuts, fresh cilantro, sliced green onions, and sesame seeds for added texture and visual appeal.