In a large bowl, toss red bell pepper, onion, and artichokes together with kidney, pinto, and garbanzo beans. Set aside.
In a separate bowl, whisk salt and sugar with white and balsamic vinegars until completely dissolved. Slowly whisk in olive oil. Adjust seasoning as desired.
Pour dressing over bean mixture, and toss to coat. Cover and refrigerate at least one hour before serving. Serve chilled.
