Is there any difference between the two?
What do you see?
What are you seeing?
There is a slight difference between these two questions, but it's not the typical difference between present and present progressive tenses. It's more about how long the seeing has been taking place.
"What do you see?" implies that the seeing just started. If you poke your head over a fence, your short friend might ask you, "What do you see?" And you'd say, "The batter just struck out."
"What are you seeing?" implies that the seeing has been occurring for a while. For that reason, it's much less common. If you've been spying on someone with binoculars, your spy buddy might ask you, "What are you seeing?" And you might say, "It looks like she's turning a knob. It might be a safe. She's been playing with it for 2 minutes."