From Cooking Light.

• ½ cup chopped green onions
• ½ cup chopped green bell pepper
• ½ cup chopped red bell pepper
• 15.5 oz garbanzo beans
• 15.5 oz kidney beans
• 15.5 oz black beans
• 3 tbsp red wine vinegar
• 2 tbsp olive oil
• 1 tsp black pepper
• 1 tsp lemon juice
• ½ tsp salt

Whisk together the vinegar, oil, pepper, lemon juice, and salt. Mix the first six ingredients together, then stir in the viniagrette. Chill before serving.