How to Make It
In a large, shallow dish, toss the onion with 1 1/4 tablespoons kosher salt. Let stand until the onion releases most of its liquid, about 15 minutes, then stir in the maple syrup and chili paste. Add the chicken breasts and turn to coat completely. Cover and refrigerate for at least 30 minutes or for up to 1 hour.
Light a grill. Remove the chicken from the marinade, brushing off most of the onion. Grill the chicken over a moderately hot fire for about 4 minutes per side, or until lightly charred and cooked through. Transfer to a platter and serve hot.