To find these 3 note chromatic runs on your guitar, take the tone intervals within a minor scale, and add the note in between, thus creating a chromatic run of 3 notes.
For example, a Em scale consists of E F# G A B C D and octave E. So in Em, the 3 note chromatics you could use would be EFF#, GG#A, ABbB, CC#D and DEbE. To put it another way, you are adding a note beween degrees Root&2, 3&4, 4&5, 6&7 and 7&root of the scale.   
By playing these across octaves, you can produce some smooth ascending / descending runs that are relatively easy to remember and play. I love playing repeating patterns that are easy to remember - for me playing the guitar is about making things as easy as you can, therefore repeating patterns and fingerings are great to play! These runs work well over minor and minor7 chords, I have chosen a  basic sequence of minor 7 chords.
Technique wise, alternate picking works well for these licks, but you can also try legato patterns and economy picking should you want to include it.

There are some quite large and fast position shifts within this example, so play the lick slowly at first, concentrating on picking accuracy, then speed it up gradually. Equipment wise, i used a Framus Diablo Custom, straight through a Boss GT6 into the computer.
Good luck with it! 

A minor

E minor