1. 1. Halve the avocados length-wise; pit and peel. Slice a thin layer from the rounded bottom of each half so that it sits flat.
2. 2. In a small bowl, combine the tomato, cilantro, scallion, jalapeno, lime juice, 1 teaspoon oil and 1/8 teaspoon salt. Add salt to taste if necessary.
3. 3. Heat the grill to high. Brush avocado halves lightly with oil; grill 1 minute a side, until lightly charred.
4. 4. Place avocado halves on a platter; spoon tomato salsa into wells. Serve immediately.