Wet the cracker breads and layer between 2 moist cloth towels for about 20 minutes.

Fry onions in hot oil, stirring often, for 5 minutes. Reduce heat to medium-low and cook, stirring occasionally, until onions are golden brown, about another 40 minutes. Season to taste with salt and pepper.

In a food processor, combine mayonnaise and spices. Whirl until blended and smooth.

Unwrap cracker bread. Spread with mayonnaise mixture and onions. Top with turkey and lettuce leaves. Roll up and slice to serve.