Cucumber salad (GF, PF, SF, NF)

2 cucumbers (thinly sliced)
1 red onion
2 tblsp vinegar or 2 tblsp lemon juice
2 tblsp low-fat sour cream or 2 tblsp yogurt
salt and pepper to taste
1/2 teaspoon sugar
1 teaspoon chopped fresh dill 

Mix cucumbers and onions together
Mix rest of ingredients together in a closed bowl and shake
Add to cucumbers, chill & serve