In a bowl, combine olive oil, lemon juice, minced garlic, dried oregano, salt, and black pepper. Add the chicken thighs and toss to coat. Let marinate for at least 15 minutes at room temperature or up to 4 hours in the fridge.
Heat a grill pan or large skillet over medium-high heat. Cook the chicken thighs for 5 to 6 minutes per side until they reach an internal temperature of 165 degrees F and have nice char marks. Let rest for 5 minutes, then slice.
While the chicken rests, prepare the bowl components. Halve the cherry tomatoes, dice the cucumber, slice the red onion, and halve the olives.
Divide the cooked jasmine rice among serving bowls. Arrange the sliced chicken, cherry tomatoes, cucumber, red onion, and kalamata olives on top.
Sprinkle each bowl generously with crumbled feta cheese and drizzle with tzatziki sauce. Serve immediately.