Combine all ingredients in a small bowl. Stir well to combine. Set aside
To prepare swiss chard, cut bottom inch off of stems and discard. Chop stems into small dice (think celery) until you reach leaves, then chop into larger dice. Set aside.
In a large skillet over medium heat, saute onion in 1 tbsp olive oil for 10 minutes stirring frequently. Season with a pinch of salt, black pepper, and smoked paprika.
Add swiss chard stems to the pan with the onion and mix together for 4 more minutes. Add swiss chard leaves and cook until leaves are wilted.
Place a tortilla in a large saute pan over medium heat. Fill tortilla with 1/3 of the swiss chard mixture and 1/4 cup feta cheese. Place second tortilla on top. Press down to flatten quesadilla, you can use something heavy like another pan to keep the tortilla flat. Cook for 3 minutes or until the cheese begins to melt. Carefully flip over and cook for another 2 minutes.
Repeat with remaining tortillas
Serve with salsa and (optional) sour cream and slices of avocado