In a medium bowl, toss 1/2 head cored and thinly sliced radicchio, 1 tbsp. lemon juice, 1 tsp. EVOO, and a large pinch of salt. In the bowl of a food processor, combine 1 can (14 oz.) cannellini beans, drained and rinsed, 1/4 cup each EVOO and fresh parsley, 1 tsp. lemon zest and 1 tbsp. lemon juice, 1 clove garlic, and 1 tsp. kosher salt. Process until smooth. On each toasted bread slice, spread 1/2 tsp. Calabrian chili paste and 1 1/2 tbsp. bean mixture and top with some radicchio.