Prep the Veggies and Beans: Chop the cucumber, tomato, red onion, and cilantro. Place them in a large mixing bowl along with the drained kidney beans.
½ cup chopped English cucumber, 1 medium tomato, 1 cup chopped red onion, 1 ¼ cups chopped fresh cilantro, 1 can
Whisk the Vinaigrette: In a small bowl, whisk together the lime juice, olive oil, Dijon mustard, garlic, and sumac (if using). Season with a pinch of salt and black pepper.
Juice of 1 large lime or lemon, 3 tablespoons extra virgin olive oil, 1 teaspoon Dijon mustard, ½ teaspoon minced garlic or garlic paste, 1 teaspoon ground sumac, Salt, Black pepper
Toss It All Together: Pour the vinaigrette over the salad and mix well until everything is evenly coated and glistening.
Let It Chill: Cover the bowl and refrigerate the salad for 30 to 60 minutes so the flavors can blend and get extra tasty.