Bulgar Salad with Grilled Red Onions

1 pound bulgar
1 large red onion, sliced into 1/4-inch slices
3 tablespoons olive oil, divided
3 plum tomatoes, diced
1 cup finely chopped flatleaf parsley
2 tablespoons finely chopped mint
1/4 cup fresh lemon juice
Salt and freshly ground pepper

Place the bulgar in a large bowl and cover with boiling water, let stand 15 minutes and drain. Brush the onion slices on both sides with the olive oil and season with salt and pepper to taste. Grill on both sides until almost cooked through, remove and coarsely chop. Place the bulgar in a large bowl, add the remaining ingredients and mix to combine. Season with salt and pepper to taste. Serve at room temperature.