This recipe was actually on their website for a bit when they took the zucchini off the menu. Now that the zucchini's back - the recipe's gone but here you go:

BLACK ANGUS CUCUMBER DRESSING

Cucumbers, grated 1 cup, packed
Yellow onion, grated 1/4 cup
Worcestershire sauce 1 tsp.
Tabasco sauce 1 dash
Mayonnaise 2/3 cup
Sour cream 1/3 cup
Salt 3/4 tsp.
White pepper pinch
White vinegar 1 1/2 tsp.
Granulated garlic 1/2 tsp.
Granulated sugar 1 1/2 tsp.

Mix all ingredients together in a mixer on low speed for 10 minutes. Pour into a container, cover and refrigerate 8 hours or overnight.