Remove membrane from the ribs and discard; reserve ribs. In a medium bowl, combine brown sugar, five-spice powder, garlic powder, chili powder, salt and pepper. Spread dry rub mixture on both side of the ribs and then place them in the slow cooker.
You may have to curl the rack of ribs along the inner wall of the crock pot to fit it in. Prepare the sticky sauce. Mix together brown sugar, honey, soy sauce, rice vinegar, sriracha, minced garlic, five-spice, and red food coloring in a small saucepan.
Pour half of the sauce in the crock pot, cover and cook for 4 hours on high or 6-8 hours on low until tender. Transfer ribs to a large baking sheet lined with parchment paper and brush with sauce. Broil for about 7-8 minutes.
Meanwhile, whisk cornstarch with water in a small bowl; reserve. Bring remaining pan sauce to a boil, reduce heat to medium, and then whisk in cornstarch mixture. Make sure to stir sauce constantly until thickened, about 5-7 minutes.
Remove ribs from oven and brush them with thickened sauce. Garnish top with sesame seeds and green onions. Serve with rice, noodles, or in a sandwich. Use the crock pot broth to dip rib sandwich into (french dip style).