For the Lemon Vinaigrette:

1. Combine the lemon juice, apple cider vinegar, olive oil, salt, pepper, red pepper flakes and sugar, in a small bowl and stir.
2. Refrigerate the unused vinaigrette .

For the Flatbreads:

1. Combine the flour, baking powder, salt and black pepper in a large bowl and mix.
2. Add the olive oil and warm water while stirring to combine into a dough.
3. Flour a clean surface and knead once or twice to form into a ball.
4. Slice the dough in half and then quarters and finally into eighths.
5. Form each piece into a ball and then roll out thin on a floured surface.
6. Heat a large griddle and place the rolled out dough on the hot griddle. When bubbles form flip over and finish cooking.
7. Place on a platter and cover until ready to use.

Plating the Tuna Salad:

1. Place the flatbread on a plate; top with the salad greens and tuna. Grate fresh Romano or Parmesan cheese over the tuna and salad.
2. Plate the melon, tomato and avocado along with the salad greens.
3. Drizzle the vinaigrette over the plate.
4. Serve with lemon wedges for garnish.