1/4 cup apple cider vinegar
2 tablespoons water
1-3 teaspoons honey
1/4 teaspoon prepared Dijon mustard OR 1 1/2 teaspoons caraway seeds OR 1 teaspoon celery seeds OR 1 teaspoon chopped fresh dill
4 medium cucumbers, peeled, thinly sliced
6 thin slices onion 

1. Mix the vinegar, water, honey to taste, and mustard (or other choice of seasoning) in a glass mixing bowl.  Add the cucumber and onion;  toss until well combined.

2. Marinate for at least 30 minutes at room temperature or refrigerate overnight.  Serve cold or at room temperature.

 – The Real Dirt on Vegetables