The right way is to specify thermal relief on the pads and be sure it’s enabled for the pour when you specify the pour area. The default values KiCad uses seem reasonable, but consult your manufacturing folks for guidance appropriate for the tools they use.
Thermal relief on the pad setting is on the second tab of pad properties (E key)
Just like there really isn’t a uniform ground, there is no uniform temperature during re-flow. It’ll probably work, but you’ll probably need to have more preheat time.
More important in my mind is that your board becomes a disposable. It’s not going to be very repairable in the absence of thermal relief. If you’re OK with that, then that’s fine.
Oz (in DFW)