SCL/SDA indicates that is the I2C protocol. You can desolder the physical connector and stick on whatever is you want to use to connect to the I2C pins on your Raspberry Pi. That's easy.
But unless you know how to write USB drivers (and if you did you would not be asking these questions), your best bet is to see if someone has already written an I2C to USB drivers so you can create a virtual USB port that is physically accepting I2C. It would have to have been written specifically for the wireless NES mini.
That would require enough software knowledge to make the firmware and drivers for both an NES mini controller and a wireless mini controller from scratch. So unless you can find someone who has tried already done exactly what you are trying to do, I would say you are hosed.