Cook onions with bay leaf in oil over medium heat until soft, about 10 minutes. Remove pan from heat, and add wine and vinegar. Return to heat, and bring to a simmer, cooking until liquid has almost evaporated, about 7 minutes. Stir in raisins and pine nuts, and season with salt and pepper. Let stand until cool; discard bay leaf.
Place a small amount of radicchio on each slice of bread. Top with a spoonful of onion mixture. Remove anchovies from oil, and place 2 on each slice.