Preheat the oven to 400 degrees.
Using a sharp knife, slice the squash lengthwise into crescents about 1/2-inch thick. Toss with 1 tablespoon warmed coconut oil, along with 1/4 teaspoon chili powder. (Or less if you’re sensitive.) Season with sea salt and black pepper and arrange in a single layer on a baking sheet. Roast until tender and golden, about 25 minutes.
Have a plate with paper towels ready. In a large skillet, warm 2 teaspoons of coconut oil over a low flame. Add the cumin, coriander, and mustard seeds and sauté, stirring, until fragrant, about 1 to 2 minutes. Add 1/2 of the split peas, and raise the heat to medium. Stir often, and cook until they have crisped and browned, about 7-9 minutes. Spread the crispy yellow peas on the paper towel. Repeat with the remaining batch of yellow peas. Season to taste with sea salt.
In a large bowl, toss the arugula, mint, and cilantro together with the olive oil and a squeeze of lemon. Add in 3/4 of the crispy yellow peas and toss.
To serve, divide the arugula mix evenly in the center of 2 or 4 plates, depending on portion. Divide the squash among the plates, and top with the remaining crispy peas. Best served immediately, so the crispy peas remain crisp!