In a blender, purée 2 green onions, gochujang, soy sauce, garlic, sesame oil, vinegar, canola oil and hoisin sauce until smooth. Adjust seasoning with salt and pepper. Coat the chicken with the marinade and marinate overnight or for at least 4 hours.
Preheat the oven to 350°F.
Place the rice, 4 cups of water and a pinch of salt in a saucepan. Bring to a simmer, reduce to low, cover, and cook until the grains are tender, about 20 minutes.
Arrange the chicken on a baking sheet, discarding the marinade. Roast until cooked through, about 22-28 minutes, flipping halfway through.
For the slaw, blend the sambal oelek, garlic, fish sauce, vinegar, ginger, oil and gochujang in a blender until smooth. Toss the bok choy, cabbage, carrots and bell pepper with the dressing until well coated.
To serve, divide the rice between plates, top with gochujang glazed chicken and serve with kimchi slaw on the side, topped with green onions and sesame seeds.