In a small bowl, add the blackberries, jalapeno, lime juice, and maple syrup. Mash a few of the berries and mix well.
Heat a medium pan over medium heat and add the pepitas, sesame seeds, and red chili flakes. Toast the seeds, stirring constantly for 1-2 minutes until they brown and pop. I recommend running your overhead fan, as the chili can be strong when toasted. Immediately transfer the seed mix to a small dish.
Wipe out the pan from the seed mix and heat it to medium-high. Add the shallots and cook them for 1 minute or so until they soften.
Stir in the garlic and rosemary. Mix for about 15 seconds.
Add the white beans and ½ cup of vegetable broth. Mix well, and stir the bottom of the pan to loosen any stuck-on shallots.
Once the broth starts to simmer, use a potato masher to mash the beans, adding more broth until they are creamy. If desired, leave a few whole beans for added texture.
Cover the beans on low heat if you need time to heat the tortillas.
For oil-free crispy tortillas, heat them directly on the oven rack at 400 F (200 C) for 2 minutes until they are firm and crispy.
To make the tostadas, add a layer of white beans over the tortillas, then top with blackberry salsa and the seed mix. If desired, add toppings such as shredded lettuce, mashed avocado, or diced tomatoes.