In a small bowl, whisk together the lime juice, sriracha, agave nectar and salt. While whisking slowly pouring in the olive oil.
The Salad:
Preheat the oven to 375 degrees F.
Lightly coat a baking sheet with cooking spray. Place the butternut squash on the tray. Sprinkle the olive oil, cumin, salt and pepper over the squash and toss to coat.
Roast the squash until tender when pierced with a fork, 25 to 30 minutes.
In a serving bowl, toss the arugula, black beans and pepitas. Add the roasted butternut squash and the dressing, and toss again.