Heat oven to 400 F (200 C). Toss sweet potato with 1 Tbsp (15 mL) oil, oregano, and 1/4 tsp (1 mL) salt. Spread out on rimmed baking sheet and roast until tender, about 20 minutes.
In medium saucepan, place quinoa, 1 3/4 cups (435 mL) water, and 1/4 tsp (1 mL) salt. Bring to a boil, reduce heat to medium-low, and simmer, covered, until liquid is absorbed and quinoa is tender, about 12 minutes. Set aside, covered, for 5 minutes and then fluff quinoa with fork.
In skillet over medium, heat 2 tsp (10 mL) oil. Add tempeh and chili powder; heat, stirring occasionally, for 5 minutes, until browned.
In blender, combine cilantro, jalapeño, sour cream, lime juice, 1 Tbsp (15 mL) oil, agave or honey, cumin, garlic, and 1/4 tsp (1 mL) salt. Process until smooth, scraping down sides as needed.
In large bowl, toss together sweet potato, quinoa, tempeh, black beans, red onion, tomatoes, and pumpkin seeds. Add cilantro dressing and toss together.
All contents of this salad can be chilled together in airtight container for up 3 days. Any optional toppings, such as avocado, should be added just before serving.