So, you found this web page. It has blue Hershey's kisses slapped all over the background. Why do they have faces? What really ARE those things?
There are all kinds of slimes, but let us begin with the basic slime as shown in the Dragon Quest games. A basic slime has an oval body with a small, tapered point on the top. Two googly eyes and a large red smile are the only facial features.

Slimes are essentially the symbol of DQ/DW. Why? They are a common enemy, and a cute one at that. Blue slimes always tend to be one of the first - if not the first - monster encountered in the game. Red slimes and metal slimes are also prevelent in the early DQ games. A "Metal," called a Metaly in the recent re-translations of Dragon Warrior I, II, and III, is especially sought-after due to the high amount of experience gained when he is defeated. The question is if you can defeat a Metal - they have high evade rates and tend to run from battle.
In Japanese, slime is pronounced as soo-ra-ii-mu. None of the syllables are emphasized. In romanji, it's written as "suraimu." This is how it's written in katakana, and what each syllable means:

Here are some additional questions regarding slimes.
How do slimes reproduce?
There are those online who debate if slimes are produced sexually or asexually... take your pick. It should be pointed out that King Slimes are formed by 8 blue slimes jumping atop each other and POOF! A king slime appears. In the DW/DQ Monsters games, all monsters reproduce and leave an egg. You also need a male and female monster in order to create that egg, and that points towards sexual reproduction. (And yes, slime hentai does exist in Japan....) It seems that slimes produce sexually AND asexually.
Do slimes have special relationships with other animals or people?
Actually, yes. In DQIV (my favorite of the series), there are several instances where slimes and cats are very good friends. There are also two excellent examples of major characters befriending slimes. Rosa is locked away in her tower with a slime as her main companion. Ragnar and Healie (a Healer, called a hoimi slime in Japan) travel the world together as Healie seeks for a way to become human.
Here is an example from Dragon Quest 4Koma Manga Theater 5:

How many kinds of slimes are there?
Many. With every new game, Enix creates new kinds of slimes. Dragon Quest/Warrior Monsters 2 has a massive slime family for players to breed. The 26 kinds are: Babble, BoxSlime, DrakSlime, FangSlime, GoldSlime, GranSlime, HaloSlime, Healer, KingSlime, Metabble, MetalKing, Metaly, MimeSlime, Pearlgel, RockSlime, Slabbit, Slime, SlimeBorg, SlimeNite, Snaily, SpotKing, SpotSlime, TreeSlime, Tropicgel, WingSlime, and WonderEgg. If you need further details on how to breed these slimes, check www.gamefaqs.com or the Prima Official Strategy Guide.
What does a slime taste like?
Wow, what an ecchi question. I think Jell-O has a slime-like consistency, so perhaps they taste like blue Jell-O. If I ever meet a slime and eat a chunk out of it, I'll let you know. *sweatdrop*
Do slimes react the same way as slugs do to salt?
This is pure speculation, but I'd say no. I haven't seen salt used as a weapon in DQ yet. ^^
You need a life. Badly.
No argument there, but if you have time to flame people about not having a life, then you haven't much of one, either. :>