Combine squash and extra-virgin olive oil in bowl and season with the chili flakes and salt.
Place on sheet tray lined with parchment paper in one even layer.
Roast at 500 degrees for approximately 8-10 minutes, rotating with a spatula every few minutes for even cooking.
Cook until lightly colored and tender.
In a medium saute pan heat the oil and add the onions.
Cook over medium heat, stirring occasionally, until the onions are deep golden brown.
Add the vinegar and maple syrup and reduce quickly until syrupy.
While the onions are still warm, combine with the roasted squash, cool and reserve.
Drizzle bread with extra-virgin olive oil and cook in a nonstick pan over medium heat until golden and crispy.
Spread 2 tablespoons of ricotta over the toast, then top with about 1/3 cup of kabocha mix and spread evenly.
Cut the toast into 4 and top with mint, a drizzle of extra-virgin olive oil and coarse sea salt.