1. Cube avocados into medium bowl of cold water; drain well. Place in large bowl. Add lime juice and mash coarsely. Mix in watercress; season to taste with coarse salt and pepper. DO AHEAD: Can be made 2 hours ahead. Cover and chill. 2. What to drink: Pommery NV Brut Royal Champagne ($40) is kosher and pairs well with the latkes and the rest of the menu.
