Clean the squid by cutting it open, removing the insides, eyes, and beak. Score the surface in a crosshatch pattern with a sharp knife, being careful not to cut all the way through. Slice diagonally into bite-sized pieces.

Wash and cut the vegetables as you like.

Quickly stir-fry the squid until just firm, then remove from the pan. Stir-fry the vegetables until about 60% cooked. Add the squid back in, toss everything together, then immediately turn off the heat and cover with a lid.