In a small bowl or large liquid measuring cup, whisk together the orange zest, orange juice, soy sauce, vinegar, honey, red pepper flakes and olive oil until well combined. Add in the cornstarch and whisk again to combine. Set aside.
For the skillet:
Add the olive oil to a large skillet set over medium heat. When hot, add in the carrots, peppers and eggplant. Cook, stirring occasionally, until tender, about 6 to 8 minutes. Stir in the garlic and ginger and cook until fragrant, about 30 seconds. Add the cashews, green onions and sauce to the skillet and stir to combine. Cook for another 1 to 3 minutes, stirring frequently, until the sauce has thickened. Taste and season with salt if needed.
Serve over rice and garnish with sesame seeds and/or fresh basil, if desired.