Set a large colander in the sink. Place the rounds of eggplant into the colander. Sprinkle the tablespoon of salt over the eggplant and toss with your hands to evenly coat each slice in the salt. Let the eggplant rest for 20 minutes.
While the eggplant is resting, make the peanut ginger sauce. In a medium bowl, whisk together the peanut butter, maple syrup, coconut aminos, garlic, and ginger. Once you have a smooth and unified sauce, set aside.
Preheat your grill to high. Place one clean kitchen towel and a large baking sheet on the counter.
The eggplant should have let off quite a bit of moisture. Rinse the eggplant thoroughly, tossing the slices with your hands to get all of the excess salt off. Then, transfer the rinsed eggplant slices to the clean kitchen towel. Pat the slices with the towel until they are completely dry.
Transfer the dry eggplant slices to the baking sheet. Evenly spray both sides of the eggplant with the oil. Season the slices with salt, pepper, and chili flakes (if using) on both sides.
Place the eggplant slices on the grill. Cook until char marks appear on the undersides, about 3 minutes. Using tongs, flip the eggplant slices over. Continue to cook until char marks appear on the other side and eggplant has softened, about another 3 minutes.
Transfer the grilled eggplant to a serving platter. Drizzle the peanut ginger sauce evenly over the top of the eggplant. Garnish the dish with sliced green onions, sliced mint, and chopped peanuts. Serve immediately.