Split the vanilla bean lengthwise, scrape the seeds into a 3-quart saucepan, and add the vanilla bean, apricots, sugar, lemon juice, 1/8 tsp. salt, and 2 Tbs. water. Bring to a boil over medium-high heat, stirring to dissolve the sugar and salt. Reduce to a simmer and cook, stirring occasionally, until the apricots are very tender, 3 to 5 minutes.
Meanwhile, prepare an ice bath by filling a large metal bowl with a few inches of ice and water. Have ready a second metal bowl that will fit into the ice bath.
Transfer the apricot mixture to the second bowl and put the bowl in the ice bath. Stir occasionally until cool, about 5 minutes. Discard the vanilla bean and purée the apricot mixture in a food processor.
Put two small scoops of the ice cream in each of 6 tall, narrow 14-to-16-oz. glasses. Top each with about 2 Tbs. of the apricot sauce. Repeat with another layer of ice cream and sauce. Add about 1/2 cup of the sparkling wine to each glass. Serve immediately, with straws and spoons.