While using click command in Selenium can you use screen coordinate?

To click on specific part of element, you would need to use clickAT command.  ClickAt command accepts element locator and x, y co-ordinates as arguments - clickAt (locator, cordString).

DefaultSelenium.ClickAt Method

It clicks on a link, button, checkbox or radio button. If the click action causes a new page to load (like a link usually does), call waitForPageToLoad.