There is no way to choose a preferred display currency for your project. By default, the currency displayed on your project is determined by its country of origin*. That means if your banking and identity information is based in, say, Canada, your project goal and reward costs will automatically be displayed in CAD. If you’re in the UK they’ll be in GBP, and so on.
Kickstarter does offer backers the option to set a preferred display currency when browsing projects. However, pledges will always be collected in the project’s native currency, not in a backer’s preferred display currency.
*For projects launching from Denmark, Norway, Sweden, Switzerland, and Poland, creators now have the option to choose whether to run their project in their country’s native currency, or in Euros.