If one party of a tenants in entirety property deeds his interest to a 3rd party w/o consent of the other party, who owns the property?

The quick answer is that one party can not transfer his/her interest to a 3rd party without consent of the other party. Since tenancy in the entirety is limited to married couples, if the marriage is dissolved the property may automatically change from tenancy in the entirety to tenancy in common, in which case each party has an equal share and has the ability to sell his/her share without the consent of the other.