On wikipedia I read a few times that Italy invaded Albania because it needed space to house people, as well as creating a foothold in the Balkans.
But it sounds a little ridiculous to me and I can't tell if the wiki is just being sarcastic I guess.
I'm sorry for any errors in my post, but it is pretty late, I'm writing on my phone and English is not my first language.
Italy already tried to conquer Albania during WW1 and actually made it an Italian protectorate until 1920.
Things get a little complicated at that point. The Triple Entente promised Italy a protectorate over Albania, but after Woodrow "14 points", the Italian government was afraid that the Entente would not respect the secret treaty, and tried to ask for support to the Greek government.
The Venizelos–Tittoni agreement was a secret non binding agreement where Venizelos, the PM of Greece, pledged to support the Italian claims over Vlorë and the establishment of an Italian protectorate over Albania in the upcoming Paris conference. Too bad that Venizelos decided to release the agreement to the public, since he didn't really like an Italian protectorate so close to home. This reveal sparked armed revolts in Albania and a bunch of popular unrest in Italy too, so the Italian government had to retreat from Albania and put an end to the protectorate. But they sure didn't end it willingly.
Now, a huge part of Mussolini's propaganda for WW2 was funded in the "mutilated victory". In short, Italy had fought in WW1 and lost a lot of men, yet they did not receive what they have been promised by the Entente.
Albania and Greece were also vital to the control of the Mediterranean sea, so that couldn't hurt. I've never heard anything about any overpopulation issue.