Cit the baguette in half crosswise, then cut off the ends. Using a wooden spoon, push the bread out from inside to hollow our each half, leaving 1/2" thick walls. Reserve the crumbs for another use.
Mince the eggs, stir in watercress, cream cheese, mayonnaise, mustard, salt, pepper, curry powder and cayenne.
Holding each half of cut baguette on end, pack filling into bread shells with wooden spoon. Cut 3/4 of the way through each baguette at 1" intervals, so that guests can pull off individual sandwiches. Wrap tightly in plastic wrap and keep chilled until serving.