You obtain ability chunks from "scrubbing" your gear, 20,000 cash to wipe all the subs clean, regardless of how many subs are on the gear. You then get the corresponding subs back as ability chunks. if you use 10 of the same ability chunks, you can add it to any gear as a single sub. Adding more of the same sub on the same gear (adding a second quick respawn will cost you 20 chunks, and a third will cost you 30 chunks). You can also obtain ability chunks by themselves from Salmon Run as rewards. You can get meal tickets and food tickets from Salmon Run as bonuses. You can also get MEAL tickets from single player in the hub world and in some levels.
Ability chunks are extremely grindy, HOWEVER don't get too discouraged, as you are no longer boned if you end up with cruddy gear. Just scrub and try again, and again, and again, and once you get enough ability chunks you can customize your own gear. Again, insanely grindy, and it's a daunting task at first, but it's definitely so much better than the system in the first game. If you have any more questions, ask away!
