• Trim the ends from the delicata squash. Cut the squash in half lengthwise and scoop out the seeds with a spoon, then cut each half crosswise into ¼-inch-thick half-moons. 
• Peel the onion and cut in half lengthwise, then crosswise into ¼-inch-thick slices.
• Remove the stem, ribs, and seeds from the bell pepper; cut the pepper into ¼-inch-wide strips. 

In a large frying pan over medium-high heat, warm 1 to 2 tablespoons oil until hot but not smoking. Add the squash and cook, stirring occasionally, until starting to soften, 4 to 6 minutes. Add the onion, bell pepper, and ¼ cup [½ cup] water, season with salt and pepper, and cook, stirring occasionally, until the vegetables are just tender, 3 to 4 minutes. Transfer to a plate and season to taste with salt and pepper. Wipe out the pan if using to heat the tortillas. While the vegetables are cooking, start preparing the rest of the meal.

• Cut the tomatoes in half. 
• Juice half the lime; cut the remaining half into wedges for garnish. [Juice 1 lime; cut the remaining lime into wedges.]
• Coarsely chop the cilantro; set aside half for garnish. 
• Crumble the queso fresco if needed; set aside for garnish.

In a medium bowl, stir together the tomatoes, lime juice, half the cilantro, and 1 to 2 teaspoons oil. Season to taste with salt and pepper. 

On the stovetop directly over a flame, or in the same pan used for the vegetables over medium heat, warm the tortillas, turning once, until just pliable and warmed through, about 30 seconds per side. Transfer to a clean kitchen towel, cover, and keep warm.

Set out the tortillas, vegetables, tomato salsa, lime wedges, queso fresco, and remaining cilantro. Invite everyone to assemble their own fajitas.