Well, I have to warn you on Balugon's advice, while he thinks as non christian would do. Considering visiting a nude park - I don't think that is a good idea, because you should keep your body only to your husband/wife.
I'd say it is natural to for a man to desire a woman's body, that's a healthy sexual inclination. Lust is I think an uncontrolled desire. As christians we have to learn self controll as well. Sexuality is not wrong if it's used the proper way, but when you cannot controll it, than it can ruin your life. You can't prevent noticing a beautiful woman on the street, but what you do next is vital. Do you caress the sinfull thoughts, or you can controll them. Be aware, that most sins come through the eye. First you take notice of something, than you want it, you start thinking about it, and eventually the sin is commited, if you're not allert. I am a young single man myself, and I know that I can only deal with these issues only when I am in strong relationship with God. I used to have a 'What Would Jesus Do' bracelet. It helped me in situations, when I was reminded of God's presence at all times. Keep your mind set on the right things, focus on God, be active serving God. If you're busy working for the Lord, the devil won't be able to feed your mind with sinful thoughts. Trust God above all, because He never lets us in bigger temptations, than what we can handle.