Transferring apk files from your dinc will probably not work well on your Photon. These may be proprietary apk's. In the least, they will FC. At the worst, they may brick your device.
But if you are so inclined to try and transfer HTC Dinc apps, to a Motorola device, then try this.
Find and download the stock factory rom.zip for the Dinc. Unzip, and extract the specific apk. Copy it to the photon, and install it via some type file manager.
Use a backup app, like backup pro or Titanium backup, to backup the app to SD, insert sd in Photon, and use TU to restore it..
Either way, I think you will probably open the proverbial can full of worms, and fubar your device. The reason you don't see Dinc's proprietary apps on Market, is because they are proprietary.
But hey, the worst you can do, is fubar your device
...... and who knows, it may run just fine..