Are bagels in Dunkin Donuts Kosher? What about if with cream cheese?
The regular bagels as is are fine. The cream cheese needs a hechsher.
Can they be toasted?
If it’s a regular toaster, yes.
If it’s a toaster-oven, and they bake ham sandwiches there too, it might be a problem. You need to see if it’s clean and they use clean trays when they do it. Or ask them.
Even if ham was cooked at the oven or other non Kosher items why would it be a problem as long as their aren’t pieces of them that are put to the bagels
That’s the concern. You need to confirm that you will not be getting meat or it’s flavor from a different sandwich.