Of course you can grill the eggplant if you’ve got the grill going.
1 pound eggplant 1/2 pound tomatoes 1 to 2 fresh hot green chiles, such as bird's-eye, Indian long, or serrano, finely chopped 1/2 small onion, minced 2 tablespoons chopped cilantro 2 teaspoons finely chopped fresh mint 2 to 3 teaspoons fresh lime juice 3 teaspoons extra-virgin olive oil Kosher salt and freshly ground black pepper
Preheat broiler, with rack in top third of oven. Line a rimmed baking sheet with foil. Use a fork to prick eggplants all over; prick tomatoes in a few places. Place both vegetables on prepared sheet and broil, turning occasionally, until charred all over and very soft. Remove as done and place in a sieve set over a bowl; let cool.
When cool enough to handle, peel eggplants and tomatoes. Remove and chop pulp finely; place in a bowl. Add chiles, onion, cilantro, mint, lime juice, and 2 teaspoons olive oil; season with salt and pepper. Mix and taste for balance of seasonings, adjusting as necessary. Serve warm or at room temperature. If not eating immediately, refrigerate until ready to serve, or up to 2 days.