5 to 6 cups of cucumber, peeled & thinly sliced
1 medium onion, thinly sliced
1/2 cup white vinegar 
1/2 cup water
1/2 cup sugar
1 cup mayonnaise
1/8 tsp. celery seed
1/4 tsp. dill weed
In a sauce pan combine the vinegar, water and sugar. Bring to a boil and boil for 3 minutes. Let cool, add mayonnaise, celery seed, and dill weed. Stir until creamy.  
Combine cucumbers and onions in a medium bowl. Pour sauce over cucumbers and onions, stir until well coated. Cover and refrigerate for 1 hour before serving.