For the dressing: To the pitcher of a high-speed blender add the raspberries, olive oil, Dijon mustard, vinegar and salt. Puree on high for about 1 minute, scraping down the sides halfway through, until emulsified. Set aside.
In a large bowl, toss together the radicchio, escarole, fennel and salt. Begin by adding half the dressing and tossing well to coat. Taste the salad to determine if it needs more dressing. Depending on the size of your lettuces it may take all the dressing. Divide the salad among 4 salad bowls and top evenly with the olives, sesame seeds and raspberries.