Can a US Citizen living in Canada, get a license to carry firearms while visiting the US? [closed]

Regarding the license to carry (aka, CCW), yes, probably. As with all things firearm, the laws vary by state. Some states will issue licenses to out of state residents. In fact some states will let you do it by mail. Best would be to get a license in the state that you plan to spend time in, this way if there is a problem it can be quickly validated. An alternative is to get a license in a state that has a reciprocity agreement with the state(s) that you will be spending time in. (You can see what states recognize whose licenses at a site like usacarry.com). Also note that some states do not require licenses for concealed carry. And in other states, its very difficult to get a license at all, even for residents.

Purchasing a handgun may be more difficult. I consulted a friend of mine who's a firearms trainer on what's required for a handgun purchase. He said their store would require a driver's license or state ID from his state, or proof that you owned residential property in the state (along with, obviously, an instant background check). And he believes the rules are similar in most other states. So the question may be, do you still have a US driver's license? If not, you may need to renew it.

Ultimately, given your situation, since the laws vary so much from state to state, it will be best for you to visit a gun store the next time you are in the US and verify from them their state's requirements. They can probably also provide info on their state's CCW license requirements. Some may have some modest training requirements for licenses (usually a few hours attending classroom training).