1. Cut the zucchinis in half lengthwise and scoop out the insides, leaving a 1/4 inch shell to stuff. An apple corer is the best implement for this, but a serrated grapefruit spoon or regular spoon will also work. Reserve the scoopings for other recipes.
2. Mix together the remaining ingredients except the olive oil and water and stuff the zucchinis with them.
3. Dot with the olive oil.
4. Pile onto a steamer rack and pressure cook 3 minutes, dunking the pressure cooker into cold water to stop cooking; or steam 20 minutes or until the zucchinis are tender.
Serve cold as an appetizer.