Can a sales person who is required to wear suits in his salaried position then claim the expense for suits on his taxes?

Unfortunately clothing is not a deductible expense even when required to wear certain dress for employment . This includes business attire and uniforms.

You cannot deduct the cost of travel to and from work, or other expenses, such as most tools and clothing.

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/deductions-credits-expenses/line-229-other-employment-expenses/salaried-employees.html