Melt butter in a frying pan over low heat. Add the garlic and stirfry until aromatic. Put in the rest of the tangy plum sauce ingredients and simmer briefly for 10-15 minutes, until sauce is thick. Dish out and put aside.
To blanch squid:
Clean squid and peel away the membrane. Separate the head and hood. Cut hood into rings, or score in a crisscross pattern then slice into pieces.
Bring a pot of water to boil. Blanch the squid in boiling water briefly. Remove and drain well.
Heat the oil in a wok or frying pan. Add garlic and ginger slices and stirfry until fragrant.
Add onion, stink beans, capsicum, and carrot. Toss briefly.
Add 3 tablespoons of the tangy plum sauce into the wok along with the squid and cucumber. Toss well over high heat.