Sort and wash beans; place in a large bowl. Cover with water to 2 inches above beans; cover and let stand 8 hours or overnight. Drain beans. Place beans in a large saucepan. Cover with water to 3 inches above beans; add bay leaf. Bring mixture to a boil. Reduce heat; simmer, uncovered, 1 hour and 15 minutes or until tender. Drain beans; discard bay leaf. Place beans in a large bowl; sprinkle with 1/4 teaspoon salt and pepper. Let stand 5 minutes. Drizzle with 1 teaspoon oil; toss gently to coat.
Heat 4 teaspoons oil in a small nonstick skillet over medium heat. Add garlic; sauté 45 seconds or just until garlic begins to brown. Remove from heat; stir in juice. Place arugula in a large bowl; sprinkle with 1/2 teaspoon salt. Add warm bean mixture, garlic mixture, and onion; toss gently to combine.