I dont think you can create a website to load at a set resolution but you can make it be a specific width and height. Assuming you are using CSS then you need to set the width of the wrapper/mainbody to auto rather than a fixed value
This sets the width to be automatic so that it strecthes with the resolution but will only go as far as 700px wide thanks to the min-width value.
margin: 0 auto;
Could do the same for the height using min-height