How to Make It
For marinade, zest the entire lemon (yellow part only, about 1 tablespoon), and place zest in a large mixing bowl. Add juice (3 tablespoons) of the lemon to bowl (don't worry if seeds are also added). Add 1 tablespoon olive oil, 1/2 teaspoon salt, 1/4 teaspoon pepper, and sugar; stir to combine. Add chicken tenders; stir to coat with marinade. Set aside to marinate for 15 minutes.
While the chicken marinates, make the sauce: Combine all sauce ingredients in a blender. Cover and blend on medium speed until smooth, about 20-30 seconds. Set sauce aside.
Using tongs, place marinated chicken on the grill; discard marinade. Cook about 4 minutes; flip the tenders and cook an additional 3-5 minutes or until cooked through. Divide tenders among 6 plates (about 2 tenders each), and drizzle each portion with 1 tablespoon sauce. Garnish with lemon slices. Store leftover sauce, covered, in refrigerator up to 3 days.