Place the meat in a bowl. Add the onion, ginger, cumin, coriander, Asian chili powder, salt, chili and lemon juice, and mix well with your hands, turning, mashing and kneading to blend the ‑avors and to get a smooth texture. Cover and refrigerate the mixture for at least an hour.
Mix in the fresh coriander and mint leaves. With wet hands, mold the mixture into 4 equal-size patties or, to create sliders, 8 equalsize patties. Refrigerate the patties at least for 1 hour.
To grill the patties: Preheat the grill to high. Lightly oil the grate with vegetable oil – pour oil onto a paper towel, then hold the towel with tongs to wipe the oil onto the grate. Place the patties on the grill directly over the heat. Cook about 2 to 3 minutes per side for medium doneness, brushing with oil to prevent sticking, turning once.
While the meat is cooking, prepare the rolls. Slice and toast the bread on the grill. Serve the patties sandwiched between the bun halves.
Tip: Do not press down on the patties with a spatula during cooking—this only squeezes out the juices and dries out the meat.