Press tofu for at least 10–15 minutes to remove excess moisture.
Cut all veggies and tofu into evenly sized pieces for even grilling.
Make the marinade:
In a small bowl, whisk together olive oil, balsamic vinegar, mustard, garlic powder, salt, and pepper.
Marinate:
Add all chopped vegetables and tofu cubes to a large bowl or container. Pour the marinade over the top and toss to coat evenly.
Let marinate for at least 30 minutes (or up to 4 hours in the fridge for more flavor).
Assemble the skewers:
Thread the marinated tofu and vegetables onto skewers, alternating for color and texture variety.
Grill or bake:
To grill: Preheat grill or grill pan to medium heat. Cook skewers for 10–15 minutes, turning occasionally, until vegetables are tender and slightly charred.
To bake: Preheat oven to 425°F (220°C). Place skewers on a parchment-lined baking sheet and roast for 20–25 minutes, flipping halfway through.
Serve:
Remove from heat and serve warm, optionally with hummus, pita, or over a bed of quinoa or rice.