Chipolte gives dish some zip.
Bring a pot of water to a boil and gently steam the beans, al dente. Drain and plunge in cold water to halt cooking. Drain again and set aside. In sauté pan heat olive oil. Add onions, chipotle and tomatoes. Gently steam the beans. Plate the lettuce and top with sauté and beans then the tuna. Drizzle with lemon juice, dill, salt and pepper.