Toss 2 bunches asparagus and 1 quartered red bell pepper with olive oil, salt and pepper. Grill over medium-high heat, turning, until tender and charred, 3 minutes for the asparagus and 6 minutes for the pepper. Thinly slice the pepper and toss with 2 tablespoons olive oil and 1 teaspoon red wine vinegar; spoon over the asparagus. Top with chopped chives.