1. Bring potatoes and water to cover to a boil; cook 15 minutes. Add beans and eggs; cook 5 minutes. Drain. Cut potatoes in half lengthwise, and cool 10 minutes.
2. Peel eggs under cold running water, and cut into wedges.
3. Gently stir together roasted red bell peppers, next 3 ingredients, potatoes, and beans. Whisk together garlic and next 6 ingredients; gently toss with potato mixture. Arrange on a serving plate with tuna and eggs.