In a large pot, set a steamer basket over boiling water. Dice the tempeh into 1-inch cubes and steam, covered, for 5 minutes or until soft. Set aside.
In a saucepan, heat the vegetable and sesame oils over medium-high heat, and saute the garlic for 15 seconds. Add the sliced onion and peppers and stir fry for 3 to 4 minutes.
Stir in the ginger and soy sauce and add the steamed tempeh. Stir fry for 3 more minutes. Serve immediately over hot rice.