I'm not Finchy, but you get Psionic abilities/ a way to spend Exp as a Delve reward for beating the boss of Synthech Admin & Research. (The Building at the North-East of Westview.)
Oh, I see, sorry!
You can acquire Psionic skills by using the chair in the east wing of your Safe House. There are many other upgrades there as well, that you can acquire by exchanging EXP.
The southern purple section of the upgrade area pertains to Psionic abilities, so you can find several there. Hope this helps!