In a small bowl, combine the tbsp of orange juice, tbsp soy sauce, tbsp cornstarch, tbsp maple syrup and whisk until it's combined.
Cube your tempeh into bite-size pieces. Add your tempeh to the marinade and toss until it's coated. Set it aside for at least 20 minutes.
After 20 minutes, place your cubed tempeh on a parchement-lined baking sheet and bake for 20 minutes, flipping halfway throughout.
FOR THE SAUCE
In a saucepan over medium-high heat, whisk together the soy sauce, rice vinegar, orange juice, maple syrup, ginger, red pepper flakes and cornstarch. Whisk continuously until it's thick and bubbly (about 5 minutes) and turn the heat off.
Removed the baked tempeh from the over, toss the cubes into the sauce, stir and serve.