Slice the tempeh into bite-sized cubes.
Mix soy sauce, olive oil, garlic powder, and smoked paprika in a bowl.
Add tempeh cubes to the marinade and let sit for 10 minutes.
Heat a non-stick skillet over medium heat.
Add the marinated tempeh to the skillet.
Sauté for about 5 minutes until golden brown.
Add chopped vegetables to the skillet.
Stir-fry for another 5-7 minutes.
Adjust seasoning with more soy sauce or hot sauce if desired.
Garnish with fresh cilantro before serving.