1 pound (16 ounces) fresh lump crabmeat
1 small sweet onion, chopped fine
1/2 cup canola oil
1/2 cup ice cold water
1/3 cup cider vinegar
1/2 teaspoon salt
Freshly ground black pepper
Pinch of cayenne pepper (optional)
Scatter half of the chopped onion in the bottom of a serving bowl. Add half of the crabmeat. Layer remaining onion followed by remaining crabmeat.
Combine canola oil, cider vinegar, salt, pepper, and cayenne and whisk thoroughly. Pour over the crabmeat and onion mixture, followed by the ice water. Press mixture down gently with a spoon. Cover and refrigerate for 2 hours or up to 24 hours.
Serve on a pile of butter lettuce with saltine crackers. Garnish with sliced lemons and oranges, if desired.