Scrub potatoes. Cut potatoes into 1/2-inch slices. Brush both sides of each potato slice with oil. Sprinkle with salt and pepper.
For a charcoal grill, place potato slices on the rack of an uncovered grill directly over medium coals. Grill for 15 to 20 minutes or until potatoes are tender and browned, turning occasionally during grilling. (For a gas grill, preheat grill. Reduce heat to medium. Place potato slices on grill rack over heat. Cover and grill as above.)
Arrange potato slices on a serving platter. Sprinkle with dried tomatoes and capers. Spoon creme fraiche into a small serving bowl; sprinkle with chives. Serve potato slices warm or at room temperature with creme fraiche.
In a small bowl stir together whipping cream and sour cream. Cover with plastic wrap. Let stand at room temperature for 2 to 5 hours or until mixture thickens. When thickened, cover and chill in the refrigerator until serving time. Stir before serving.