Shouldn't it be; "Do you see the boy?" For the suggested question; "can you" there should be "możesz".
Can this mean both? Do this mean both? "Can you" and "do you"? Wait a minute... o_O
It does mean both ;) Unless one uses "can you" very literally, which is of course possible as well.
No, they are not. Some forms may be identical between singular and plural, but usually they are different.
I know times have changed, but we were always taught that 'can' was a 'non' word, unless talking about a (tin) can, and we were never allowed to say 'can I' or 'can you', but 'may I' or 'will or would you'. But in this case, is it a correct exchange for 'Do you see the boy'? and could it be used in any similar phrase?