How to Make It
Combine olives, oil, 1 tsp. of the lemon zest and 1 Tbsp. of the lemon juice, parsley, sunflower seeds, and crushed red pepper flakes in a bowl; stir well. Set aside.
Combine tuna, dill, mayonnaise, mustard, remaining 1 tsp. lemon zest and 1 Tbsp. lemon juice, salt, and black pepper in a bowl; stir well.
Preheat broiler to HIGH. Divide tuna salad evenly on top of each slice of bread; place on a foil-lined baking sheet. Sprinkle cheese evenly over top. Broil for 1-2 minutes, until cheese melts. Spoon olive salsa over toasts.