Cook beans in boiling water 2 minutes or until crisp-tender; drain. Rinse under cold water; drain.
Heat oil in a large nonstick skillet over medium-high heat. Add onion, and sauté 3 minutes or until onion begins to brown. Add garlic; sauté 1 minute. Add beans, juice, oregano, and red pepper; cook for 1 minute or until thoroughly heated. Remove from heat. Add capers, salt, and black pepper, tossing to coat.