While the quinoa cooks, in a large skillet over medium, melt the margarine. Add the zucchini, carrot and squash. Saute until soft, about 4 to 5 minutes. Stir in the garlic powder, ginger, salt and pepper.
Once the quinoa has cooked, drain it and add to the vegetables. Toss to mix, then set aside.
Using a mandoline or vegetable peeler, cut the cucumbers lengthwise into 32 thin strips.
Brush eight 4-ounce ramekins with olive oil. Arrange a double layer (about 4 slices) of cucumber slices around the inside of each ramekin. Pack 1/2 cup of the quinoa mixture into the center of each ramekin. Set aside.
To prepare the vinaigrette, squeeze the juice from half of the grapefruit. Cut the other half into segments.
In a small bowl, whisk together 3 tablespoons of the juice, the olive oil, salt and pepper.
Place an overturned serving plate on top of each ramekin and invert. Carefully remove the ramekins, then drizzle each timbale with a bit of the vinaigrette. Garnish each with grapefruit segments.