1. To make the salsa, pulse the tomatillos in a food processor until coarsely pureed. Add the cilantro, jalapeño, lime juice, and salt and pulse until well combined. Set aside.
2. To make the quesadillas, gently combine the hot beans, the olive oil, lime juice, salt, garlic, and scallions. Keep warm. Spread about 2 tablespoons goat cheese over half of each tortilla. Using a heaping 1/4 cup of the bean mixture for each tortilla, press the beans into the goat cheese. Trim the salmon slices to fit half of the tortilla and lay the slices with the trimmings over the beans. Fold the tortilla in half and press the sides together. Set aside.
3. To make the salad, whisk together the orange juice, lemon juice, and mustard. Whisk in the walnut oil, salt, and pepper. Place the arugula in a large bowl and loss with the yellow peppers. Toss with the dressing.
4. Heat a large nonstick skillet over medium-high heat. Working in batches as necessary, place the quesadillas in the skillet and cook until browned and heated through, about 1 to 1-1/2 minutes per side. Cut each quesadilla into 3 triangles.
5. Spoon a little of the salsa onto the center of 6 large plates. Place 3 quesadilla triangles around the salsa. Arrange the salad in a circle around the edge of the plates and serve immediately.