Does swapping screens in default screen mode evolve inkay in Pokémon Sun.
No you evolve Inkay by flipping the 3DS upside down. Citra emulates motion control with right mouse click and drag. This method does evolve Inkay.
Do you know how to do it on the phone I really need it
Your phone usually has native gyro support, which Citra should be able to tap into. Try just flipping your phone upside down (make sure that you don’t overdo it to the point where the Citra window “flips” around).