Defrost the squid, pat dry, and coat with all-purpose flour.

Cut the cucumber lengthwise and slice diagonally. Slice the yellow bell pepper thinly and cut the onion into thin slices.

Mix the marinade ingredients (sugar, salt, vinegar, pepper, olive oil, and water) in a shallow dish.

Add the cucumber, bell pepper, and onion to the marinade and mix well.

Heat salad oil in a frying pan over medium heat and fry the squid until cooked through.