Cook Pasta: Bring salted water to a boil. Add gluten free pasta and cook 1 minute beyond the package instructions. Drain and rinse with cold water immediately.
Prep Veggies & Protein: While pasta cooks, dice red onions, cucumber, halve the tomatoes, chop parsley, slice pepperoncini, and grill (or dice pre-cooked) chicken breasts.
Make Dressing: In a small bowl or jar, combine olive oil, vinegar, lemon juice, Dijon, honey, garlic, seasoning, salt, and pepper. Whisk or shake until emulsified.
Combine: Add cooked pasta, vegetables, chicken, and feta into a large salad bowl. Pour dressing over and toss gently until fully coated.
Chill & Serve: Refrigerate for at least 30 minutes before serving. Toss again and garnish with more parsley or lemon zest if desired.