This grilled eggplant salad with yogurt is zesty and delicious! Serve it as a side dish alongside burgers and chicken, or as a vegetarian main dish over greens and couscous.
Start the coals or heat a gas grill for medium-high direct cooking. Make sure the grates are clean. If using wooden skewers, soak for about 30 minutes prior to cooking.
Cut the eggplant into 3/4-inch slices. Brush with the oil and sprinkle with salt and pepper to taste on both sides. Thread the tomatoes onto skewers. (If desired, you can add additional tomato skewers as a side.)
Put the eggplant on the grill directly over the fire. Close the lid and cook, turning once, until the slices develop deep grill marks and are tender, 5 to 8 minutes per side; brush the eggplant with more oil if it starts to look dry. Grill the tomatoes at the same time, turning once, until charred and tender, about 5 minutes. Transfer both to a cutting board and chop into bite-sized pieces.
Put the yogurt, garlic, scallions, mint, and lemon juice in a large bowl and stir to combine. (You can prepare the recipe to this point up to a day before; cover and refrigerate the eggplant and yogurt mixture separately.)
Add the tomatoes and eggplant to the yogurt and stir to coat. Serve at room temperature or chilled, and garnish with sumac if you like.