Prep produce: Peel cucumbers if needed and roughly chop. Slice scallions, seed and chop jalapeño, mince garlic, and chop dill and mint.
Blend the base: Add cucumbers, yogurt, lemon juice, sherry vinegar, garlic, dill, mint, jalapeño, scallions, olive oil, salt, and pepper to a blender.
Thin and puree: Pour in the cold water and blend on high until very smooth and silky. Add more water a splash at a time if you prefer a looser texture.
Season to taste: Adjust salt, pepper, and acidity with more lemon juice or vinegar as desired.
Chill: Transfer to a covered container and refrigerate at least 30 minutes for flavors to meld.
Serve: Stir, ladle into bowls, and garnish with diced cucumber, cherry tomatoes, croutons, and a light drizzle of olive oil.
Notes
Make it vegan by swapping Greek yogurt for a ripe avocado or vegan yogurt. For extra chill, blend in a few ice cubes. Gazpacho thickens as it rests—thin with cold water as needed. Keeps refrigerated for up to 2 days.