Select the grating attachment for your food processor and attach to machine. Rinse zucchini, pat dry, and split in half lengthwise. Scoop out seeds with a spoon to form a canoe. Discard seeds and feed zucchini into processor. Remove grated zucchini from processor and place onto a clean, dry kitchen towel. Squeeze towel around grated zucchini firmly to remove liquid. Peel potatoes, then cut and shape them to fit into processor feed. Grate potatoes, place on another dry towel, and squeeze dry. Transfer zucchini and potatoes to a large mixing bowl. Beat eggs in a small bowl with a fork and add to mixture. Add grated onion, chopped parsley, 1 teaspoon canola oil, and ½ cup matzah meal, continuing to add more if necessary. Season with salt and pepper to taste; blend well.

Heat frying oil to medium high in a large, heavy-bottomed skillet. Spoon zucchini and potato mixture into the hot oil and shallow fry for 2 minutes, or until golden brown, on each side. Pat dry with paper towels. If cooking several batches, place latkes on a plate in a warm oven, uncovered. Serve with sour cream, fresh chives, and applesauce.