In most worksites and other public areas, little policing is needed to ensure that the policy is followed. The policy should be discussed with your leasing and housing attorney, and it should be known that after instituting the policy you may be considered liable to keep the building smoke-free.
The same policies you would use for eviction for other rule violations could be applicable, so long as you have outlined the smoke-free policy properly on the lease. This may involve giving a set number of warnings before threat of eviction. In general, if your tenants realize you are determined to keep your property smoke-free, most will follow the policy.