Place the sliced cucumbers, red onion, fennel, radishes, mint leaves, and jalapeño in a large salad bowl.
Season with salt, black pepper, sumac, grated garlic, olive oil, and lemon juice. Mix well until everything is coated.
Spread the plain yogurt on a nice round or oval serving plate. Place the salad on top of the yogurt.
Garnish with chopped mint, fennel fronds, a touch of sumac, and a drizzle of olive oil.
