My general strategy for competitive X-Wing is to find a weakness in my opponent's build and exploit it, but when I played against this list:

Rear Admiral Chiraneau (46)

Calculation (1)

Commander Kenkirk (44)

Gunner (5)

Darth Vader (3)

Total: 99

...I couldn't seem to counter it at all, and this could be due to me being a noob. But it seemed like it was doing well against experienced players too. What I'm wondering is whether there is a way to beat this build using small ships alone, as I have no large ships yet. Whatcha think?

Use some blockers, Ties or Z-95's. With no EU's on either ship it shouldn't be to hard to do.

If you rob him of his focus tokens then his two ships are totally defenceless.

Calculation seems odd on chirpy...if you take focus as your action, means your blanks are unchangeable, and also you won't be able to use calculation unless you get at least 2 focus when at range 1-2.

I'd say based on the build, kenkirk is your primary target. Between vader and gunner I'd argue he's a bigger offensive threat than chirpy, and with his native ability, he's obviously the bigger defensive threat as well.

As for what to bring yourself? Well a swarm would probably be the most logical. A howl tie swarm would be the strongest of course.

Some bwings with fcs and mangler could be deadly. Efficient attacks with lots of crits coming in will really make them have a bad day.

Swarms.

I usually manage to kill or near kill a decimator in one round with 6 ships.

I try go for vader first.

The more dmg you do to him the more it'll hurt himself to use the ability

The list you posted biggest weakness is to swarms

With no boosting (Engine upgrade) he'll not be able to arc dodge.

Once you block one, you just open up with all your other ships

I've found rebel swarms with at least one stress bot ywing really good in todays two ship meta