Roast the Peppers: Place peppers over an open flame until charred on all sides. Transfer to a container with a lid, close it, and allow them to steam until the skin softens. Peel, deseed, and chop into 1cm pieces.
Blanch the Green Beans: Blanch green beans in boiling water for 6–7 minutes, then transfer to an ice bath to cool. Drain and set aside.
Prep Remaining Ingredients: Finely chop the red onion, and rinse the canned beans thoroughly. Allow beans to drain.
Assemble Salad: In a large container with a lid, add the green beans, four-bean mix, roasted peppers, red onion, and mozzarella if using.
Make Dressing: In a bowl or jar, whisk together olive oil, red wine vinegar, honey, minced garlic, salt, and pepper.
Combine and Marinate: Pour the dressing over the salad ingredients. Close the lid and shake to combine, or stir well. Adjust seasoning to taste.
Chill and Serve: For the best flavour, refrigerate overnight before serving. Adjust tanginess by adding more vinegar or more honey/sugar if needed.