Mix the sauce ingredients together. Set aside.
Heat a large skillet over medium-high heat with 1 Tbsp olive oil. Add half the chicken pieces (1 pound) to the skillet, spacing out as much as possible. Cook for 2-3 minutes per side until golden brown and cooked through.
Transfer to a clean bowl and repeat with the second pound of chicken. Once the second pound is cooked, transfer it to the bowl with the first and set aside.
Carefully wipe away any excess oil in the pan and add the sauce to the skillet and cook for 1-2 minutes, stirring until it thickens. Turn off the heat and add the chicken pieces to the sauce. Toss to coat. Garnish with toasted sesame seeds and serve over rice, cauliflower rice, or your starch of choice.
For the cucumber crunch, mix the chili oil, tahini, lime juice, and cilantro together in a large bowl. Add the sliced cucumber and radishes, tossing everything together.