They can mean the same thing. Little boy, have you finished your lunch? Little boy, have you eaten your lunch. Both might be checking that ALL was eaten. They can mean slightly different things. Hi, good to see you. Have you eaten your lunch". Does not have to mean eaten it ALL. Hi, good to see you. Have you finished your lunch". Does not have to mean eaten it ALL. Hi, good to see you. Did you finish your lunch". Seems to mean that you must have eaten it ALL, as otherwise using "did" doesn't make much sense.