Welcome to Android Central! There should be a widget for that. Open your App Drawer, then tap Widgets. There's a Contact widget, which is for a single contact. Drag that to a homescreen, and when you release, your People app will open up and prompt you to select a contact. Once you've selected a contact, then when you tap that widget, the contact will pop up in a window, and you'll get the option to call or send a text.
There are also Direct Dial and Direct Message widgets that allow for one-touch actions. They will ask you to select a specific phone number from a contact, which then allows a single touch of the widget to perform the action.