This "soup and salad" is an elegant combination of sweet and savory. Gazpacho is a classic Spanish chilled soup usually made with tomatoes; here we add watermelon for a sweet, summery twist. A simple crab salad flavored with fresh herbs on the side completes the meal.
In a large bowl, mix together the first 6 ingredients. Season with salt and pepper, to taste, and refrigerate.
In the bowl of a food processor or blender, combine the first 7 ingredients. Season with salt and sugar, to taste. With the motor running, slowly stream in the olive oil until emulsified.
Transfer to bowls and serve with the crab salad on the side.