Season both sides of the chicken with salt and pepper.
Heat a large sauté pan over medium-high heat.
Add the vegetable oil, and once hot carefully add the chicken skin-side down. Sauté until golden brown, 5 to 6 minutes.
Flip the chicken and cook 2 more minutes. Transfer to the slow cooker.
In a medium-size bowl, whisk together the hoisin sauce, honey, soy sauce, hot water, ginger, and garlic. Add to the slow cooker.
Cover and cook the chicken skin-side down on high for 3 to 4 hours, or 5 to 6 hours on low.
If possible, flip the chicken halfway through cooking so the sauce infuses the surface of both sides.
If desired, transfer chicken to a foil-lined sheet pan skin-side up and broil 10-inches from the top of the oven until skin is crisp, about 5 to 7 minutes.
Glaze the chicken with the sauce. Garnish with sesame seeds and cilantro.
Notes
Sauteing the chicken before adding to the slow cooker adds more flavor and color to the skin, and renders extra fat from the chicken to prevent the sauce from becoming too greasy. You can skip this step, however, make sure to trim excess skin and fat from the chicken before adding to the slow cooker.