Remove or hide red colour from trackpad on laptop
My first thought would be to use 1/8" black pinstripe tape for the long straight red parts.  Cut the tape to length before applying it to the touchpad edges.  Never apply the knife tip against the touchpad.

The rounded over corners are probably too tight for the tape to bend around smoothly but it might be worth a try.  If the thin tape alone can't make the bend, Oracal makes wider rolls (sold from the same amazon page above).  You could apply some of the 1/2" pinstripe tape to a non-stick surface (like a plastic cutting board) then cut out the corner curve using an xacto-blade.  Again, keep the knife away from the touchpad.

Please note that I have recommended tapes that cost over 20 dollars total which puts you within 10 bucks of the cost of this black carbon-fiber skin which appears to be specifically made for your laptop.  (The same manufacturer also has a charcoal wood skin that makes me consider buying a Y720 for myself.  I do a lot of shou-sugi-ban finishes on my woodwork, so the charcoal style is perfect for me).