Prep the ribs: Pat the ribs dry. Remove the thin membrane from the back of the racks by sliding a knife under it and pulling it off with a paper towel.
This helps the ribs get tender and lets the sauce soak in.
Season generously: Sprinkle both sides with salt, pepper, smoked paprika, and onion powder. Rub it in so it sticks.
Make the sauce: In a bowl, whisk together honey, soy sauce, ketchup, brown sugar, minced garlic, rice vinegar, Worcestershire, sesame oil, and sriracha (if using).
Load the slow cooker: Cut the ribs into 3–4 rib sections so they fit. Arrange them in the slow cooker and pour the sauce over the top, turning once to coat.
Cook low and slow: Cover and cook on Low for 6–8 hours or on High for 3–4 hours, until the ribs are very tender but not completely falling apart.
Thicken the sauce: Carefully transfer ribs to a sheet pan.
Pour the cooking liquid into a small saucepan. Bring to a simmer. Stir together the cornstarch and cold water, then whisk it into the sauce.
Simmer 2–3 minutes until glossy and thick.
Glaze and caramelize (optional but recommended): Brush the ribs with the thickened sauce. Broil on high for 3–5 minutes until the edges char slightly and the glaze bubbles. Watch closely to avoid burning.
Finish and serve: Brush with more sauce.
Sprinkle with sesame seeds and green onions. Serve with extra sauce on the side.