In a bowl, whisk together tamari, rice vinegar, maple syrup, minced garlic, and sriracha to create the marinade.
Slice tempeh into ½-inch thick pieces and add to the marinade. Let marinate for at least 20 minutes, turning occasionally.
Meanwhile, rinse quinoa and cook in water or vegetable stock according to package instructions (typically 15 minutes). Fluff with a fork when done.
While quinoa cooks, prepare vegetables by shredding carrots, chopping green onions, and thinly slicing radishes.
Heat coconut oil in a large pan over medium-high heat. Remove tempeh from marinade (reserve marinade) and cook for 3-4 minutes per side until golden and slightly crispy.
Pour reserved marinade into the pan with tempeh and cook for an additional 1-2 minutes until sauce thickens slightly.
Divide cooked quinoa between two bowls and top with marinated tempeh, shredded carrots, green onions, and radish slices.
Garnish with microgreens, sesame seeds, and hemp hearts if desired. Serve immediately.