Thinking of textures I think I might prefer the creamy flavorful flan first, especially
if the flan were to be a nice small starter size, then the crisp salad to follow before moving on to the main entrée.
What's for dessert??? *just curious* smileys/smile.gif
p.s. another consideration might be the guest count and whether or not your flan w/tomato sauce will be served warm. You might find it easiest to serve a warm-ish flan dish first (and get it out of the way) then follow with an easier-to-assemble-between-courses salad before moving on to the main dish.