First, give chicken thighs a quick once-over and trim off any large pieces of fat. You don’t need to be super thorough – just get rid of the obvious bits. Leave the smaller fat pieces as they’ll help keep the meat tender during cooking.
In the slow cooker, whisk together the honey, soy sauce, minced garlic, and grated ginger. The mixture will look a bit thin and separated at first – that’s totally normal. Add the black pepper and give it another quick stir.
Add the chicken thighs to the slow cooker, using tongs to turn each piece so it’s well-coated. Try to arrange them in a single layer if possible, but some overlap is fine since they’ll shrink as they cook.
Cover and cook on LOW for 4-6 hours or HIGH for 2-3 hours. You’ll know the chicken is done when it’s tender enough to shred easily with two forks – if it’s still tough to pull apart, give it another 30 minutes.
Once the chicken is tender, carefully remove the pieces to a plate, leaving the sauce behind. The chicken should be so tender it might start falling apart as you lift it – that’s exactly what we want!
Now for the sauce: in a small bowl, whisk the cornstarch and cold water until completely smooth (using cold water prevents lumps). With the slow cooker turned to HIGH, stir this mixture into the cooking liquid. It’ll look cloudy at first but will clear up as it thickens.
Let the sauce bubble away for about 5 minutes, stirring occasionally, until it’s thickened enough to coat the back of a spoon. You should be able to draw a line through the sauce on the spoon and have it hold for a moment.
Return the chicken to the slow cooker and gently toss to coat with the thickened sauce. Let it sit for about 5 minutes to rewarm and soak up some of that delicious sauce.
To serve, transfer to a serving dish and sprinkle with sliced green onions and sesame seeds. The green onions should be cut right before serving so they stay crisp and bright green.