In a small bowl, whisk together the dill, vinegar, and oil. Fold in crumbled feta cheese. Season with pepper, to taste. Set aside until ready to dress salad.
Saute Canadian bacon in a nonstick 10-inch skillet over medium-high heat until crisp, about 3 minutes. Remove bacon bits to a paper towel-lined plate to drain.
On each of 4 salad plates, arrange in alternating layers: the tomato slices, onion slices, and lettuce wedges. Sprinkle with the Canadian bacon bits and divide vinaigrette evenly over the salads. Serve immediately.