The Leap Motion Controller has two near-infrared cameras with an infrared-transparent window, which operate in the 850 nanometre +/-25 spectral range so would not be be suitable for this use. Our image sensors and lens optics have zero efficacy in the thermal long wave infrared spectrum.
If you wish to access the images directly I recommend reading the LeapC documentation available here which will guide you through it however I would recommend exploring the FLIR One and FLIR Lepton modules.