How to Make It
Light a grill. Brush the eggplant slices with 3 tablespoons of the olive oil and season with salt and pepper. Grill the slices over moderately high heat until softened and lightly charred in spots, about 10 minutes. Let cool slightly, then cut each slice into bite-size pieces.
In a large bowl, whisk the balsamic vinegar and lemon juice with the remaining 3 tablespoons of olive oil and season with salt and pepper. Add the eggplant, cherry tomatoes, arugula, feta cheese and mint; toss gently and serve.