If desired, season chicken tenders with salt and pepper. Cook chicken in hot oil for 8-10 minutes, turning once, until no pink remains.
For the vinaigrette, combine remaining oil, vinegar, thyme, sugar, salt and pepper; shake to combine.
To serve, arrange chicken, cucumber ribbons, sliced tomatoes, olives and feta cheese on serving plates. Drizzle vinaigrette over the top.