Cut the cabbage into thin strips.
Cut the onion into thin half rings. Cut the red onion into half rings and set aside.
Remove the stem and seeds from the bell pepper, then cut into strips.
Assemble the salad: combine all the vegetables and onions in a bowl.
Add vinegar, salt and ground black pepper to taste to the salad. Mix thoroughly.
The salad is ready. Serve the coleslaw in portions, garnished with fresh mint leaves.