A commercial siding contractor should be able to discuss their qualifications, experience, and certifications with you, as well as provide references from previous commercial projects they have completed. They should also be able to provide you with an estimate for the project and explain their process for completing the work. Additionally, they may discuss any warranties or guarantees they offer for their work, as well as their safety protocols and insurance coverage. It is important to thoroughly research and compare multiple contractors before making a decision.