Yes, contact them. This is known as “cold calling”.
You may be interested in companies near you but you haven’t seen any job listing on their websites. Contact them directly by telephone and find out if there will be any upcoming vacancy in your niche. If you do not want to use the telephone, send them an email and attached a professional resume to your email.
Of great importance, make sure you do a research on these companies before contacting them so that you can converse with them smartly, by showing them how much you know about their company.
Overall, cold-calling is an effective way of unleashing the hidden job market.