Preheat oven to 450 degrees Fahrenheit. Wash and trim asparagus, removing tough ends; cut spears in half and place in large bowl with sliced onions, peppers, celery and garlic. Toss vegetables together with balsamic vinegar and olive oil; mix well and allow to marinate at room temperature 15 minutes. Coat a large flat baking sheet with food release spray and spread asparagus mixture evenly in pan; sprinkle with sea salt and roast 20 minutes at 450 degrees Fahrenheit or until vegetables start to brown. Serve hot.