raise one's foot
蹺 centers on lifting or raising one's foot, as in stepping up or tiptoeing.
蹺 combines 足 (foot) with 堯, which likely contributes the sound and the idea of being high or raised, together suggesting lifting the foot.
The left side 足 means foot, and the right side 堯 looks like a tall mound with legs. Picture a foot stepping up onto a high mound: raising one's foot.
For キョウ, imagine a person raising their foot to step over a giant kyo (きょ) sound effect bubble: kyo -> キョウ, as the foot lifts high.