Cut the tempeh into 1/2-inch cubes and set aside.
In a small bowl, whisk together the peanut butter, tamari, maple syrup, garlic powder, ginger powder, lime juice, sriracha, and water until smooth.
Heat the toasted sesame oil in a large non-stick skillet or wok over medium-high heat.
Add the tempeh cubes to the skillet and sear for 5-7 minutes, turning occasionally, until all sides are golden brown and crispy.
Add the broccoli florets, sliced red bell pepper, and snap peas to the skillet with the tempeh.
Stir-fry the vegetables for 3-4 minutes until they are bright green and crisp-tender.
Pour the peanut sauce over the tempeh and vegetables, tossing constantly for 1 minute until the sauce thickens and coats everything evenly.
Remove from heat and serve immediately.