I'm recently separated and my wife denying me visitation to kids.

You don't mention if there is an existing court order. If there is no court order regarding visitation times and contact methods then you should legally be able to visit your children although that risks all sorts of possible retaliation like the mother seeking restraining orders, etc. THe best option is to either file a motion for custody and/or visitation with the court if there is no existing action that has been filed or file a motion to enforce litigants' rights if there have been prior orders that she is violating. If you are unsure, it is best you consult with a family law attorney.