Combine the first 6 ingredients (1-6) in a small bowl and mix together. Add 1 TBS (7) of extra virgin olive oil and mix until salad is coated and incorporated then refrigerate.
Meanwhile, place the reserved 1 TBS olive oil in a small non-stick skillet over a medium heat and allow temperature of oil to come up (around 1 minute). Add the spinach and sauté until wilted, about 2-3 minutes. Add the tomato sauce and feta cheese and stir ingredients until feta is partially melted, about 3 minutes. Remove from heat and let stand.
Slice open a European roll without cutting through and lay 2-3 chicken tenders on the bottom half. Pull out some of the dough on the top half to form a pocket to hold the salad. Spoon salad into the pocket. Spoon spinach and feta sauce over the chicken tenders and serve.