Preheat broiler to high. Brush baguette slices with olive oil. Place on large baking sheet. Broil 1 to 2 min. per side or until toasted. Set aside.
To make a relish, in bowl, stir pickles with onion, parsley, mustard seeds and vinegar. Let stand 15 min. for flavours to marinate.
Spread mustard on each baguette slice. Top with slice of meat. Garnish with ½ tsp (2 mL) of pickle mixture (there will be some left over for another use.)