Android Bitcoin Wallet freshly installed, two addresses. Why two? First off, I am rather new to Bitcoins — will be obvious after I asked my question I guess. I have read some theory about it, like it's a distributed crypto-currency based on the Bit Torrent protocol, but I still have some difficulty putting everything together.

I have freshly installed Android Bitcoin Wallet on my phone, just wanted to start somewhere. I opened the preferences and I see I have two addresses without a label — which I guess I shall define. My first question is : why are there two addresses?

I understand an address is like an SSH private public (EDIT: sorry for the confusion, seems obvious indeed) key and I think I understood it's best to have one address for my phone, one for my computer... whatever. Since I read an address shall be a single-use token, is one of them for giving and the other for receiving bitcoins?

Since an address is a single use token does that mean I should create an address each time I want to pay using bitcoins? What about receiving bitcoins then? How do people send bitcoins if change my addresses constantly?

And what if I delete an address? Will it have an effect on bitcoins I'd eventually "collected"?
You are asking multiple questions, which is not how this website works. Also: all of them have been answered several times already if you search a little. I'll try to answer some anyway, to take away some of your misconceptions, which should help you back on the right track.

Misconception: Bitcoin is not based on the BitTorrent protocol. It has nothing to do with it. Bitcoin uses a peer 2 peer network, BitTorrent does too. But neither were the first or are all that similar.

Misconception: An address is NOT like an SSH private key. An address is "like" a public key (not exactly, but that distinction is not important right now). An address is what you give to someone else to have them pay you.

Hidden inside the wallet is the private key or more precisely in current wallets: the Master key from which multiple private keys are generated. If you make a backup of your wallet (which you should do!) you will get to see that master key: it's simply a list of 12 or 24 English words.

The address is used to receive bitcoins. The private key is what you need to be able to spend them. But the private is pretty much invisible to you, you don't need to care as long as you have the Master key backed up (and protected!) properly.

Address re-use is very much discouraged, for privacy reasons. Once you "use" an address, the wallet will automatically prepare a new address for the next use.

The specific wallet app you are using generates two addresses in advance to get you started.

I don't think you can delete an address in this app.

It is possible to have multiple devices use the same Master key, but it will mean that if one of those devices gets compromised and someone steals your Master key, you will lose ALL your money. It's probably better to keep things seperate until you're ready for more advanced setups. (multi-signature for example)