My girl played a trick on me yesterday by pulling my chair away when i was about to sit. I lost it badly, and slapped and canned her... Feeling v guilty now... How can I make myself not resort to force when it comes to disciplining in the future?

Thar's a terrible trick to play on anyone in the 1st place. Your child will remember for a long long time that it isn't fun to play this silly trick ..... I suppose this is 'tough love' .... try to be extra nice to her in the coming wkend but take the opportunity to teach her that her action was wrong & should never be repeated on anyone ever again ....................

I also wish to discipline my kids without canning... But don't know if possible

One suggestion is to use 'time out'. If you had seen the 'SuperNanny' TV series, the 'time out' is one of the most used strategies employed. If the child does something wrong, he/she is ordered to stay in one corner, away from the rest of the family (for a short while) and to reflect on what he/she had done wrong, and is allowed to re-join the family only after she promised to behave.
Sometimes I take away computer priviledges if my kids misbehave. If serious offense, I will ban them from the computer for a day. If really serious, 3 days or even a week.
Also both parents gotta agree on the punishment and must see it thru. No point threatening to punish and not carrying it out or giving in to the kids.

I second leongmart suggestion. Works really well with cheeky ones. They tend to slowly reflect on things they do.

Understand how you feel, I too wish I can avoid canning as discipline, but it's hard. Kids need to learn

leongmart's solution is the most ideal when it comes to nurturing and discipline.
a cane is a non-living thing that inflicts pain and therefore the end result?
your kid will probably remember it and there is a possibility of them hating you in future
if all you do is scold harshly and cane them each time they make a mistake.
i won't deny that children tend to be playful at times but really,
depending on the situation, is there a need to cane them for tiny wrong doings?
(the situation that you mentioned seems like a act of mischief, a harsh reprimanding should do the trick)
and you mentioned feeling guilty after the heavy punishment.
it's a little too late don't you think?
here's something that majority should probably think about before they resort to the cane talk

"What is the single lesson that I want my child to remember from this incident?"

Easier said than done? I disagree.
YOU have a choice to react in a moment of anger or to simply nurture them from mistakes.