Are you considered to have "performed an attack" even when no dice are rolled, such as with the original Blinded Pilot or a HWK with weapons failure? If so, does that mean other effects such as Tactician and FCS are able to activate?

For reference:

Blinded Pilot -

The next time you attack, do not roll any attack dice.

Then flip this card facedown.

Fire Control System - After you perform an attack, you may acquire a target lock on the defender.

My reading is that an attack has still been "performed" without dice and FCS can activate. Is that correct?

Correct, this is covered on page 8 of FAQ v4.2.3

A ship with Blinded Pilot assigned to it may still use abilities that trigger after performing an attack, such as Darth Vader, Gunner, and Luke Skywalker, even though no attack dice are rolled.

You can also use abilities that add results to the attack roll (e.g. Accuracy Corrector).