Is it possible to assign a hotey to a certain weapon ? ( just like in oblivion)

use the Favorite Key when you have your Inventory/Magic UI up, and press Q for your Favorite List, now select and item and press 1-8 or Num 1-8

Yeah you can after it is favorite you just assign it to the key you want. I just wish you could assing a set to each key. Such as Sword / board, Dual wield or even 2 spells. If there is a way I haven't figured it out yet lol.

What happens when you press the hotkey? Does it always go into your right hand first? So to equip two different weapons/spells, you'd need to press the first hotkey twice and the second one once?

It's horribly awkard to set up the hotkeys to work with dual wielding in mind. I spent awhile attempting to get my spell/sword/shield hot keys to work as intended with no luck. Sword/sword/shield combos worked just as terribly.

Skyrim's UI is a constant slap in the face so far.

You can't dual wield through hotkeys. When you hit the hotkey for your sword it goes to the main hand, hit it twice it doesn't switch it unequips. If you have a sword and magic or sword and board equipped your weapon hotkeys only change your mainhand. You have to go into your menu/favorites and equip it manually.

Thanks for answering.

The game does however remember which weapons were previously paired with each other and if a two handed weapon such as a bow un-equips your dual wield then re-selecting the weapon that was previously in your right hand also reequips the one in your left.